How are mediastinal lymph nodes structured. What is the function of the lymphatic system. Where are the key lymph node stations located. How does embryonic development shape the lymphatic system. What are the clinical implications of enlarged lymph nodes.

The Mediastinum: A Complex Anatomical Hub

The mediastinum, a crucial compartment within the thorax, houses numerous vital organs and vessels while serving as the central point for lymphatic drainage. To better understand its structure and function, medical professionals typically divide the mediastinum into three functional areas:

• Anterior (pre-vascular) mediastinum
• Middle (visceral) mediastinum
• Posterior (paravertebral) mediastinum

This classification system aids in pinpointing lesion locations and facilitates differential diagnoses. While lymph nodes are present throughout all three compartments, the anterior and middle sections contain the majority of lymphatic tissue.

Mapping Intrathoracic Lymph Nodes: The IASLC System

Traditionally, intrathoracic lymph node locations have been mapped into 14 stations based on their relationship to landmarks encountered during mediastinoscopy and thoracotomy for lung cancer. The most current and widely accepted map is the International Association for the Study of Lung Cancer (IASLC) Atlas, which has superseded previous schemas and reconciled discrepancies among older systems.

Key Lymph Node Stations

The IASLC map divides intrathoracic lymph nodes into the following groups:

• Stations 1-9: Mediastinal nodal groups
• Stations 10-14: Hilar and peripheral extra-mediastinal nodal groups

Understanding these stations is crucial for accurate staging and treatment planning in lung cancer and other thoracic pathologies.

The Lymphatic System: Structure and Function

The lymphatic system is a complex network of vessels and nodes that extends throughout the body, playing a vital role in immune function, dietary fat absorption, and fluid homeostasis. Unlike the circulatory system, lymphatic vessels are blind-ending, transporting lymph through nodes and ultimately back to the chest for return to the bloodstream via the subclavian veins.

What is lymph and how does it form?

Lymph originates from blood plasma that leaks out of capillaries into the interstitial space. This fluid contains:

• Normal macromolecules
• Lymphocytes
• Dead cells
• Potentially harmful materials (bacteria, viruses, tumor cells)

As lymph travels through the lymphatic vessels, it passes through lymph nodes, including those in the mediastinum, which act as filtration stations.

The Role of Lymph Nodes in Immune Function

Lymph nodes serve several critical functions in the immune system:

1. Filtering out potential threats and cellular debris
2. Enabling macrophages to phagocytize and break down unwanted substances
3. Allowing T-lymphocytes to sample antigens from pathogens
4. Facilitating interaction between T cells and B cells for antibody production

When immune cells become activated, lymph nodes can grow in size. Rapid growth often results in pain, while slow mitotic activity (commonly seen in cancer) typically leads to painless lymphadenopathy.

Embryonic Development of the Lymphatic System

The formation of the lymphatic system is a fascinating process that begins during the fifth week of embryogenesis, approximately two weeks after the cardiovascular system starts to develop. While some aspects of lymphatic development remain controversial, the most widely accepted theory describes the following sequence of events:

Key Stages in Lymphatic System Development

1. Channels form from diverticula off the venous endothelium (weeks 5-6)
2. Focal dilations of these channels create six primary lymph sacs (weeks 6-9)
3. Lymph vessels grow out from the sacs along major veins
4. Around week 12, most lymph sacs transform into groups of lymph nodes
5. Additional lymph nodes form along lymph vessels
6. A small portion of the sacs contributes to the formation of the cisterna chyli and thoracic duct

This developmental process lays the foundation for the complex lymphatic network that will play a crucial role in the body’s immune defense and fluid balance throughout life.

Imaging and Assessment of Mediastinal Lymph Nodes

Computed tomography (CT) is the preferred radiologic modality for visualizing mediastinal lymph nodes. On CT scans, normal mediastinal nodes appear as reniform soft tissue structures with a fatty hilum. Understanding the typical appearance and size of these nodes is crucial for accurate diagnosis and staging of various thoracic conditions.

What is considered a normal lymph node size in the mediastinum?

Generally, normal mediastinal lymph nodes measure less than 10 mm along their short axis. However, it’s important to note that healthy lymph nodes can be larger due to various factors:

• Reactive hyperplasia from acute infection
• Chronic lung diseases (e.g., emphysema, pulmonary fibrosis)

While enlarged lymph nodes can have benign causes, they are often a cause for concern and may indicate pathologic processes such as:

• Lymphoma
• Malignant metastases
• Sarcoidosis

Clinical Significance of Mediastinal Lymph Nodes

The mediastinal lymph nodes play a crucial role in the staging and management of various thoracic diseases, particularly lung cancer. Their involvement can significantly impact treatment decisions and prognosis. Understanding the pattern of lymphatic spread is essential for accurate staging and appropriate therapeutic interventions.

Common Pathologies Affecting Mediastinal Lymph Nodes

Several conditions can lead to abnormalities in mediastinal lymph nodes:

• Infections (e.g., tuberculosis)
• Nodal spread of lung cancer
• Sarcoidosis
• Lymphoma
• Occupational lung diseases (e.g., silicosis, asbestosis)

Accurate identification and characterization of lymph node involvement are crucial for differential diagnosis and appropriate management of these conditions.

Advanced Techniques in Lymph Node Assessment

While CT remains the primary imaging modality for evaluating mediastinal lymph nodes, several advanced techniques have emerged to enhance diagnostic accuracy and guide treatment decisions:

PET-CT Imaging

Positron Emission Tomography-Computed Tomography (PET-CT) combines anatomical information from CT with metabolic data from PET. This hybrid imaging technique is particularly useful in oncology, as it can help differentiate between benign and malignant lymphadenopathy based on metabolic activity.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA)

EBUS-TBNA is a minimally invasive procedure that allows for real-time visualization and sampling of mediastinal and hilar lymph nodes. This technique has revolutionized the staging of lung cancer and the diagnosis of other mediastinal pathologies by providing a less invasive alternative to surgical mediastinoscopy.

Mediastinoscopy

Although less commonly performed due to the advent of less invasive techniques, mediastinoscopy remains an important surgical procedure for directly visualizing and sampling mediastinal lymph nodes when other methods are inconclusive or contraindicated.

Future Directions in Mediastinal Lymph Node Research

As our understanding of the lymphatic system continues to evolve, several exciting areas of research are emerging that may impact the diagnosis and treatment of mediastinal lymph node pathologies:

Molecular Imaging

Advancements in molecular imaging techniques, such as novel PET tracers, may allow for more specific targeting of cancer cells or inflammatory processes within lymph nodes, potentially improving diagnostic accuracy and treatment monitoring.

Immunotherapy and Lymph Nodes

The role of mediastinal lymph nodes in the response to immunotherapy for lung cancer and other thoracic malignancies is an area of active investigation. Understanding how the immune microenvironment within these nodes influences treatment outcomes may lead to more personalized and effective therapies.

Artificial Intelligence in Lymph Node Assessment

Machine learning algorithms are being developed to assist radiologists in the detection and characterization of abnormal lymph nodes on imaging studies. These AI-powered tools have the potential to improve diagnostic accuracy and efficiency in clinical practice.

As research in these areas progresses, our ability to diagnose, stage, and treat conditions affecting mediastinal lymph nodes will likely continue to improve, ultimately leading to better outcomes for patients with thoracic diseases.

Anatomy, Thorax, Mediastinal Lymph Nodes – StatPearls

Introduction

The mediastinal compartment contains multiple critical organs and vessels and serves as the central hub for lymphatic drainage. The mediastinum is classically subdivided into three functional divisions: anterior (pre-vascular), middle (visceral), and posterior (paravertebral) mediastinum. These subdivisions are used to describe the locations of lesions, thereby helping to facilitate differential diagnoses and communication between providers. Lymph nodes (LNs) are present in all three functional compartments of the mediastinum, though most lymphatic tissue is found in the anterior and middle compartments, and the etiology of lymphatic pathology varies by subdivision. Dividing the mediastinum helps to narrow down the lengthy differential diagnoses, which can present in the thorax (including, but not limited to: infections like tuberculosis, the nodal spread of lung cancer, sarcoidosis, lymphoma, silicosis, and asbestosis). In contrast to the functional subdivisions, intrathoracic LN locations have been traditionally mapped into 14 stations according to their relationship to landmarks encountered during mediastinoscopy and thoracotomy for lung cancer. Stations 1–9 correspond to mediastinal nodal groups, while stations 10–14 represent hilar and other more peripheral extra mediastinal nodal groups.

The most current map of intrathoracic lymph nodes is the International Association for the Study of Lung Cancer (IASLC) map. The IASLC Atlas supersedes all previous schema and reconciles discrepancies among older popular systems such as the Naruke lymph node classification and the Mountain-Dresler modified version of the American Thoracic Society lymph node map.[1][2][3][4]

Structure and Function

The network of lymphatic vessels and LNs extends throughout the entire body to support the proper function of its immune system along with the absorption of dietary fats and fluid homeostasis. Unlike arteries and veins, lymphatics are blind-ending vessels that transport interstitial fluid, immune cells, and macromolecules, collectively called lymph, through LNs and back to the chest for return into the blood supply via the subclavian veins.  Lymph originates when blood plasma leaks out of capillaries and into the interstitial space. Along with the normal macromolecules and lymphocytes within the plasma, dead cells and material that may be harmful to the body such as bacteria, viruses, and tumor cells also leak out, and in turn, enter the lymph. The fluid and cells are transported back to the chest by the lymphatic vessels. Along the way, nodes, like those found in the mediastinum, sample the lymph, filtering out potential threats and unwanted cellular debris before it re-enters the blood supply. Macrophages within the lymph nodes phagocytize these unwanted substances and then break them down for recycling by the body. T-lymphocytes sample antigens from pathogens and interact with B cells to initiate clonal expansion for antibody production. With immune cell activation, LNs grown as cells within the divide. Rapid growth can cause pain, while slow mitotic activity (often seen with cancer) results in painless lymphadenopathy. [5][6]

Embryology

Lymphatic system development begins at the end of the fifth week of embryogenesis, approximately 2 weeks after the development of the cardiovascular system. While still somewhat controversial, the most prevalent theory is that the lymphatic system begins as channels forming from the diverticula off the venous endothelium. During weeks 6 through 9, focal dilations of the channels result in the creation of six primary lymph sacs. Lymph vessels then grow out from the sacs along the major veins. At about week 12 of fetal life, much of the lymph sacs are transformed into groups of lymph nodes while additional LNs form along the lymph vessels, while a small portion of the sacs goes on to contribute to the formation of the cisterna chyli and thoracic duct.[7]

Blood Supply and Lymphatics

The organization of mediastinal lymph nodes is based upon their relation to surgical landmarks: great vessels, trachea/bronchi, and pleura. On CT, the preferred radiologic modality for visualizing lymph nodes, the normal mediastinal nodes are reniform soft tissue structures with a fatty hilum.  Normal lymph nodes in the mediastinum typically measure less than 10 mm by short axis. Healthy lymph nodes can be larger, due to reactive hyperplasia from acute infection or chronic lung diseases such as emphysema or pulmonary fibrosis; however, enlarged lymph nodes are most worrisome for a pathologic process such as lymphoma, malignant metastases, or sarcoidosis.

As mentioned, based on lung cancer staging guidelines, the intrathoracic lymph nodes are divided into 14 stations, which are grouped into 7 zones. Stations 1–9 are located in the mediastinal pleural reflection, while stations 10–14 are distal to the mediastinal pleural reflection and within the visceral pleura. Stations 1, 2, 4, and 10-14 additionally have R and L designators for right and left, while station 3 has A and P designators for anterior and posterior. The intrathoracic are frequently considered in conjunction with the mediastinal lymph nodes, but extra mediastinal lymph nodes (stations 10-14) will be discussed briefly in this article for completeness.

Lymph Node Zones and Stations

Supraclavicular Zone

Station 1 (Supraclavicular): Station 1 comprises the most cranial station of mediastinal nodes. It includes LNs in the sternal notch, supraclavicular, and lower cervical regions (thus overlapping with some cervical LN maps used in head and neck cancers). The cricoid cartilage serves as the upper border of station 1. Station 1 extends inferiorly to the upper margin of the manubrium and tops of the clavicles. The midline of the trachea is used to designate which lymph nodes are 1R and 1L.

Upper Zone (Superior Mediastinal LNs)

Station 2 (Upper Paratracheal): Station 2 LNs all about the trachea and, in contrast to station 1, the left lateral wall of the trachea instead of the midline, is used as the boundary to differentiate between 2R versus 2L. The upper border of station 2 is the apex of the ipsilateral lungs and pleural spaces, and in the midline, the upper border of the manubrium. The lower border of station 2 on the right (2R) is where the inferior margin of the left brachiocephalic vein crosses the trachea, while the lower border of station 2 on the left (2L) is the superior border of the aortic arch.

Station 3 (Prevascular and Retrotracheal): The prevascular lymph nodes (3A) are all located behind the sternum and anterior to the superior vena cava and left carotid artery. The superior border is the apex of the chest (like station 2) but extends further caudal to the level of the carina. Retrotracheal LNs (3P), as their name implies, are those located in the area posterior to the trachea, likewise extending from the apex of the chest to the carina.

Station 4 (Lower Paratracheal): Lower paratracheal nodes are along the distal trachea, bordered superiorly by station 2, and extending to the level of the carina. They lie posterior to the aortic vasculature, and like station 2, the left lateral wall of the trachea instead of the midline is used as the boundary to differentiate between 4R and 4L.

Aortopulmonary Zone

Station 5 (Subarotic): These lymph nodes are also known commonly as aortopulmonary (AP) window LNs and are located lateral to the ligamentum arteriosum, the remnant of the ductus arteriosus. The lower margin of the aortic arch serves as the upper border of station 5, while the superior margin of the left pulmonary artery demarcates the lower extension.

Station 6 (Paraaortic): The para-aortic LNs lie on the anterior and lateral aspect of the ascending aorta and aortic arch, anterior and/or above the subaortic (AP window) LNs. The phrenic nerve may be used as a landmark for identifying lymph nodes that are classified as paraaortic.

Subcarinal Zone

Station 7 (Subcarinal): Subcarinal nodes lie directly below the carina and between the mainstem bronchi.  To differentiate them from the paraesophageal LNs that are found more caudal, the distal aspect of the bronchus intermedius and origin of the left lower lobe bronchus is used to demarcate the right and left inferior extensions of station 7. In most patients, this results in an inferior margin that is canted from the horizontal, given that the termination of the bronchus intermedius is usually lower than the origin of the left lower lobe bronchus).

Lower Zone (Inferior Mediastinal LNs)

Station 8 (Paraesophageal): Paraesophageal nodes are those mediastinal lymph nodes found inferior to the subcarinal lymph nodes, along with the anterior or lateral aspects of the esophagus, down to the esophageal hiatus of the diaphragm.

Station 9 (Pulmonary ligament): Pulmonary ligament nodes are associated with the pulmonary ligaments. These “ligaments” are not ligaments but represent the mediastinal parietal pleural reflections that occur below the right and left pulmonary roots (9R and 9L).

Hilar Zone + Interlobar and Peripheral Zone (Extra-Mediastinal LNs)

These lymph nodes are all outside the pleural reflection of the mediastinum but within the pulmonary visceral pleura.

Station 10 (Hilar): These LNs are found along the right and left mainstem bronchi, before they bifurcate, and are designated 10R and 10L, respectively.

Station 11 (Interlobar): Station 11 is made up of LNs located between the lobar bronchi, just beyond the bifurcation of each mainstem bronchi.

Stations 12-14 (Peripheral): These are also known as lobar, segmental, and subsegmental lymph nodes, depending on whether they are located along the lobar, segmental, or subsegmental bronchi. These LNs are infrequently seen and difficult to accurately categorize on imaging; hence many use the broad term of peripheral LNs for stations 12-14.

It should be noted that while the above classification system is the most widely utilized mapping scheme and often employed when describing mediastinal lymph nodes outside the setting of lung cancer, other disease-specific maps are appropriate in certain instances such as esophageal cancer staging.[1][8][9][10]

In addition to mediastinal lymph nodes, the thoracic duct is an important component of the intrathoracic lymphatic system. It is the largest single lymphatic vessel in the chest, beginning at the superior aspect of the cisterna chyli, at the level of the L2 vertebra. From there, it courses cranially between the posterior margin of the aorta and anterior margin of the spine until approximately the region of the T5 vertebra, where it drains into the venous system near the junction of the left subclavian and internal jugular veins. Approximately 75% of the body’s lymph fluid drains via the thoracic duct into the venous system, accounting for lymphoid drainage from the entire body, except for the right arm and right side of the head (the nodes of which drain into the junction of the right subclavian and internal jugular veins).[11][12][13]

Physiologic Variants

The budding of lymphatics from veins can be very inconsistent between individuals, and thus nodal chains demonstrate widespread variability. Notably, the most commonly identified course of the thoracic duct is present in only 40% to 60% of patients. Common presentations include thoracic ducts and corresponding cisterna chyli that present on the anatomic left, which drain into the left venous angle; thoracic ducts and their corresponding cisterna chyli that present on the anatomic right, which drain into the right venous angle; plexiform presentation; proximal and distal partial duplications of the thoracic duct; and nonexistent cisterna chyli.[13]

Surgical Considerations

Mediastinal lymph node sampling is critical to the initial diagnosis and staging of lung and esophageal cancers and lymphoma. Additionally, it is essential for detecting primary or recurrent nodal metastases in extrathoracic malignancies. This can be done by a variety of techniques employed by a variety of specialists with the technique usually guided by the location of nodal disease. Cardiothoracic surgeons may employ mediastinoscopy for the sampling of stations 1, 2R/L, 3, 4R/L, and 7. An extended mediastinoscopy or video-assisted thoracotomy (VATS) can extend their range to include biopsy of stations 5 and 6. Gastroenterologists may use esophageal ultrasound (EUS), which allows for fine-needle aspiration (FNA) of mediastinal lymph node stations 2L, 4L, 7, 8, and 9. Pulmonologists can use transbronchial needle aspiration (TBNA), as well as endobronchial ultrasound (EBUS) FNA, which allows for tissue sampling of the bilateral station 10-12 LNs (hilar and peripheral stations) in addition to 3P, station 7, and bilateral station 2 and 4 LNs. Similarly, these techniques can be used for the diagnosis of other disorders that may involve the mediastinal lymph nodes such as sarcoidosis, Castleman disease, or tuberculosis.

In addition to cancer staging, mediastinal lymphatic disorders can have other surgical implications. Chylous pleural effusions can occur when the intrathoracic lymphatic tissue is damaged, either as a result of infection/inflammation or trauma/surgery and lymph leaks into the pleural spaces. Less commonly, a chylopericardium can result if the insulting event results in a fistulous connection between the lymphatics and pericardium. If embolization of the lymphatic system is indicated after a chylothorax develops, magnetic resonance ductography has the best visualization to guide surgical intervention, but CT scans, lymphoscintigraphy, and lymphangiography can be used alternatively.[13][14][15][16][17]

Clinical Significance

In the setting of primary intrathoracic tumors, it is critical to accurately identify the station from which lymph nodes are excised/sampled, since information regarding which LNs the tumor has spread to is essential to the surgical staging of a patient’s regional disease. In the case of lung cancer, tumor involvement of ipsilateral station 10-14 lymph nodes, all of which are extrapleural, is considered N1 disease, while mediastinal LNs from stations 2-9 that are ipsilateral to the malignancy (to include subcarinal LNs for either side of disease) are considered N2 disease. Contralateral mediastinal or hilar lymph nodes, as well as station 1 LNs that have tumor cells present, are considered N3 disease. In contrast, with esophageal cancer, the N stage of the disease is determined by the number of regional LNs involved by tumor with N1 being 1-2 positive (+) LNs, N2 employed for 3-6 +LNs, and N3 designating cases with >=7 +LNs. Additionally, not all nodal stations used by the IASLC for lung cancer are considered regional LNs for esophageal cancer staging, and some stations are named differently, such as the designation of the upper, middle, and lower paraesophageal LN stations.

In addition to metastases, malignant mediastinal lymph nodes can be due to lymphomas, a group of cancers that arise from white blood cells. This group of diseases is the most frequent cause of the nodal pathology of the anterior compartment but is also a common cause of adenopathy in the middle compartment.

Mediastinal adenopathy may be due to non-neoplastic entities. Primary acute or chronic infectious and inflammatory processes occur in all compartments of the mediastinum and may result in lymph node enlargement.  Likewise, pulmonary and systemic infections such as pneumonia and the human immunodeficiency virus can result in pathologically enlarged mediastinal lymph nodes. If mediastinal lymph nodes are calcified, it helps narrow the differential diagnosis to entities such as granulomatous diseases (histoplasmosis, tuberculosis), silicosis, sarcoidosis, and treated lymphoma. When lymphatic vessels of the mediastinum are damaged, the resulting chylothorax can interfere with normal immunologic, nutritional, and respiratory function.

Enlarged mediastinal lymph nodes may be found incidentally, and guidelines for surveillance and evaluation can be found in the Journal of the American College of Radiology. For example, nodes may be particularly worrisome if they are large, asymmetric, or demonstrate FDG avidity on PET/CT scans. Nodes that are larger than 15 mm may warrant special attention, especially if there is no known explanation, such as a history of sarcoidosis. The American College of Radiology guidelines also recognize the value of categorizing lymph nodes by the aforementioned divisions, identifying abnormal LN contours, and whether the masses are solid or cystic. [3][8][12][13][18]

Figure

Mediastinal lymph nodes. Image courtesy S Bhimji MD

Figure

Mediastinal Lymph Node Stations. Contributed by Alexandra LaPore

References

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Mountain CF, Dresler CM. Regional lymph node classification for lung cancer staging. Chest. 1997 Jun;111(6):1718-23. [PubMed: 9187199]

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Craun JB, Banks KP, Clemenshaw MN, Moren RW. Sarcoidlike reaction of neoplasia causing hypermetabolic thoracic adenopathy in setting of extrathoracic malignancy: report of two cases and a review of the differential diagnostic considerations. J Nucl Med Technol. 2012 Dec;40(4):231-5. [PubMed: 23015478]

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Carter BW, Tomiyama N, Bhora FY, Rosado de Christenson ML, Nakajima J, Boiselle PM, Detterbeck FC, Marom EM. A modern definition of mediastinal compartments. J Thorac Oncol. 2014 Sep;9(9 Suppl 2):S97-101. [PubMed: 25396318]

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Rusch VW, Asamura H, Watanabe H, Giroux DJ, Rami-Porta R, Goldstraw P. , Members of IASLC Staging Committee. The IASLC lung cancer staging project: a proposal for a new international lymph node map in the forthcoming seventh edition of the TNM classification for lung cancer. J Thorac Oncol. 2009 May;4(5):568-77. [PubMed: 19357537]

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Aspelund A, Robciuc MR, Karaman S, Makinen T, Alitalo K. Lymphatic System in Cardiovascular Medicine. Circ Res. 2016 Feb 05;118(3):515-30. [PubMed: 26846644]

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Choi I, Lee S, Hong YK. The new era of the lymphatic system: no longer secondary to the blood vascular system. Cold Spring Harb Perspect Med. 2012 Apr;2(4):a006445. [PMC free article: PMC3312397] [PubMed: 22474611]

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Hsu MC, Itkin M. Lymphatic Anatomy. Tech Vasc Interv Radiol. 2016 Dec;19(4):247-254. [PubMed: 27993319]

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Ugalde PA, Pereira ST, Araujo C, Irion KL. Correlative anatomy for the mediastinum. Thorac Surg Clin. 2011 May;21(2):251-72, ix. [PubMed: 21477775]

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Liao S, von der Weid PY. Lymphatic system: an active pathway for immune protection. Semin Cell Dev Biol. 2015 Feb;38:83-9. [PMC free article: PMC4397130] [PubMed: 25534659]

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Walker CM, Chung JH, Abbott GF, Little BP, El-Sherief AH, Shepard JA, Lanuti M. Mediastinal lymph node staging: from noninvasive to surgical. AJR Am J Roentgenol. 2012 Jul;199(1):W54-64. [PubMed: 22733932]

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El-Sherief AH, Lau CT, Wu CC, Drake RL, Abbott GF, Rice TW. International association for the study of lung cancer (IASLC) lymph node map: radiologic review with CT illustration. Radiographics. 2014 Oct;34(6):1680-91. [PubMed: 25310423]

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Rice TW, Ishwaran H, Ferguson MK, Blackstone EH, Goldstraw P. Cancer of the Esophagus and Esophagogastric Junction: An Eighth Edition Staging Primer. J Thorac Oncol. 2017 Jan;12(1):36-42. [PMC free article: PMC5591443] [PubMed: 27810391]

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Johnson OW, Chick JF, Chauhan NR, Fairchild AH, Fan CM, Stecker MS, Killoran TP, Suzuki-Han A. The thoracic duct: clinical importance, anatomic variation, imaging, and embolization. Eur Radiol. 2016 Aug;26(8):2482-93. [PubMed: 26628065]

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Terán MD, Brock MV. Staging lymph node metastases from lung cancer in the mediastinum. J Thorac Dis. 2014 Mar;6(3):230-6. [PMC free article: PMC3949187] [PubMed: 24624287]

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Colella S, Vilmann P, Konge L, Clementsen PF. Endoscopic ultrasound in the diagnosis and staging of lung cancer. Endosc Ultrasound. 2014 Oct;3(4):205-12. [PMC free article: PMC4247527] [PubMed: 25485267]

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Szlubowski A, Herth FJ, Soja J, Kołodziej M, Figura J, Cmiel A, Obrochta A, Pankowski J. Endobronchial ultrasound-guided needle aspiration in non-small-cell lung cancer restaging verified by the transcervical bilateral extended mediastinal lymphadenectomy–a prospective study. Eur J Cardiothorac Surg. 2010 May;37(5):1180-4. [PubMed: 20022759]

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Atkinson C, Banks K. Imaging Idiopathic Chylopericardium With 99mTc-SC Lymphoscintigraphy and SPECT/CT. Clin Nucl Med. 2015 Nov;40(11):e508-10. [PubMed: 26284770]

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Munden RF, Carter BW, Chiles C, MacMahon H, Black WC, Ko JP, McAdams HP, Rossi SE, Leung AN, Boiselle PM, Kent MS, Brown K, Dyer DS, Hartman TE, Goodman EM, Naidich DP, Kazerooni EA, Berland LL, Pandharipande PV. Managing Incidental Findings on Thoracic CT: Mediastinal and Cardiovascular Findings. A White Paper of the ACR Incidental Findings Committee. J Am Coll Radiol. 2018 Aug;15(8):1087-1096. [PubMed: 29941240]

Dog Lymph Node Location Chart

Dogs, just like us, have several lymph nodes in their bodies which are meant to help fight infections. When a dog’s lymph nodes swell, this is often a sign of the body doing its job in trying to get rid of inflammation or an infection. The term ‘lymphadenopathy’ is used to refer to enlarged lymph nodes. When the enlargement is due to an underlying infection affecting the lymph node, the condition is medically known as lymphadenitis. Any time a dog presents with swollen lymph nodes, it’s important to see a vet sooner than later so to help the dog combat the infection, but also because often swollen lymph nodes may be indicative of lymphoma, a cancer of the lymphatic system.

 A Word About Dog Lymph Nodes

Dogs have several lymph nodes in their bodies and the most commonly enlarged are the ones found where the lower jaw joins the neck (submandibular) in the front area of the chest (prescapular), behind the armpit area (axillary), by the groin area (inguinal) and at the back of the leg (popliteal).

Lymphadenopathy, the enlargement of a dog’s lymph nodes may occur in different patterns.

For example, a dog may display a single swollen lymph node in only one area of the body (localized or solitary) or restricted to an area where the lymph nodes are usually interconnected (regional) or, as seen in multiple lymphadenopathy, there may be  multiple swollen lymph nodes in more than one area of the body (generalized or multicentric lymphadenopathy).

When lymph nodes enlarge in dogs, they may do so because of reactive lymphoid hyperplasia,  lymphadenitis and cancer.

 Did you know? The peripheral lymph nodes are the ones that are palpable (capable of being touched by hand), whereas, the internal visceral lymph nodes are those tucked inside the dog’s body which often require imaging techniques to detect any enlargements.

A Matter or Reactivity

Reactive lymphoid hyperplasia takes place when a lymph node becomes “reactive” due to inflammation or infection present somewhere in the dog’s body.  In this case, the lymph nodes enlarge because they become “reactive”upon encountering a stimulus such as bacteria or viruses and start producing an excessive amount of white blood cells.  The swelling is therefore often due to the proliferation of lymphocytes and plasma cells.

The reaction to stimulation is sort of like a burglar alarm that’s constantly on guard against intrusive antigens.  Reactive hyperplasia therefore simply means the lymph node has enlarged in response to an infection; however, there is no actual lymph node infection. Sometimes autoimmune conditions or systemic infections may be a trigger for lymphoid hyperplasia.

A Matter of Infection

Sometimes, the lymph nodes themselves become inflamed. In this case, the inflammation is within the lymph node (lymphadenitis) and is often secondary from a local infection. Basically, when a foreign invader such as an infectious agent gains access to the dog’s lymph nodes, which work as filters of the immune system, the body responds quickly by triggering an immune system response consisting of increased white blood cell production. This increased production causes the lymph nodes nearby the inflamed and infected area to swell causing “lymphadenitis.”

Often dogs have other accompanying symptoms other than the enlarged lymph nodes. For example, if a dog has an infection in a back paw, he might be limping on top of having the lymph nodes further up the leg inflamed. However, limping may, yes, occur because the foot is sore, but also because the enlarged lymph nodes may be painful, explains veterinarian Race Foster. Also, in the presence of an infection, the dog may have a fever. Fortunately, once the infection is treated, the enlarged lymph nodes should return to their normal size.

“Lymphoid hyperplasia is a condition in which the lymph nodes produce an excess of white blood cells in response to an infection elsewhere in the body. Lymphadenitis is an infection of the lymph nodes themselves, either as the primary disease or a secondary condition.” ~Dr. Karen Becker

A Matter of Cancer

Lymphoma is a possible cause of unexplained enlarged lymph nodes.  This condition is quite quick in onset, with owners often noticing painless lymph node enlargement almost overnight. Lymphoma is divided in different stages.

In stage 1, only one lymph node is affected, in stage 2, several lymph nodes sharing the same regional area are involved, in stage 3, there is generalized lymphoadenopathy, in stage 4, the liver and/or spleen is involved, and in stage 5, the bone marrow is involved.

Depending on what substage the dog is in, there may or may not be signs of systemic illness such as loss of appetite, lethargy, weight loss.

Generally, the enlargement of lymph nodes in dogs affected by cancer or lymphadenitis is quite significant with the lymph nodes presenting as five to ten times larger than normal compared to the size involving a benign reactive process, explains veterinarian Michael J. Day.

Did you know? Sometimes lymph nodes get so enlarged they cause problems. For instance swollen lymph nodes by a dog’s groin area (inguinal)may cause trouble defecating, whereas, several enlarged glands by the neck area can make it difficult for the dog to swallow, eat or breath.

“Four out of five dogs with lymphoma or lymphosarcoma have tumors that start in multiple places (multicentric). There is bilateral and symmetrical swelling of the lymph nodes without pain.”~VCA Animal Hospital

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog has an enlarged lymph node, please see your vet promptly for proper diagnosis and treatment.

References:

• Clinicians’ Brief, Lymphoma in Dogs: Diagnosis & Treatment retrieved from the web on Oct 5th, 2016
• DVM360, Cytology in evaluation of lymphoid tissue in the dog and cat (Proceedings) retrieved from the web on Oct 5th, 2016
• Cytology of Lymph Nodes, CL Davis Drs Thrall and Meuten, retrieved from the web on Oct 5th, 2016

Photo Credits:

Amazon.com: The Lymphatic System Anatomical Chart : Anatomical Chart Company: Toys & Games

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• Classic illustrations by Peter Bachin.

• Shows the lymphatic system throughout the body.

• Illustrates internal iliac lymph node, lymph vessels, lymph nodes of the stomach, pancreas, spleen and biliary tract.

• Also shows lymph vessels, lymph nodes of the small intestine, and lymph vessels, lymph nodes of the inguinal region, pelvis and the posterior wall of the abdomen.

• Size is 20 inches by 26 inches – Heavy Paper.

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Lymph Node Locations: Chart for Armpits, Head, Neck, Groin, Chest, Stomach & More

Lymph nodes, which are at times erroneously referred to as lymph glands, are an integral part of your lymphatic system, which makes up the immune system in the body. When you have a swollen lymph node, it implies that you could be infected. Lymph nodes, which happen to be small, bean-shaped tissue nodules come in several groups.

The nodes that are normally swollen or enlarged are the ones found at the rear part of your neck, its front, and on the sides as well. Lymph node locations also include in the groin, in your armpits, and below the chin.

Another set of lymph node locations comprises those found in your abdomen and chest. For this group, the only way to know whether they are swollen or not would be to take a CT scan or an X-ray.

What are the lymph nodes?

These are small cell clusters that are normally surrounded by capsules. There are normally ducts that will be going inside and outside the capsules. These cells found inside a node are known as lymphocytes.

Their job is to produce antibodies that then bind on to foreign particles, e.g., those causing infectious diseases. Besides, they also produce macrophages whose main role is to digest any debris that may be present.

Lymph nodes essentially act as the cleaner cells in a human body.

Where are lymph nodes located?

Here’s a quick chart to start with:

Where are lymph nodes located in the head, neck, armpit, etc.? Image/Macmillan

Lymph nodes serve as a major site where infectious agents and foreign substances get to interact with your immune system. One of the biggest clusters of these nodes happens to be the spleen. Your spleen serves numerous functions, key among them being the elimination of foreign substances, e.g., infections from your body.

Below is a look at some of the locations where the lymph nodes can be found.

Lymph Node locations in the head

Occipital lymph nodes are an essential part of your lymphatic system. These particular nodes can be found in the occipital part of your head. This is the part found behind your skull. When looking at lymph node locations, it is essential to note that the lymph nodes tend to be kidney-shaped or oval, and can be found throughout your body.

These nodes are linked to each other by vessels that make up your circulatory system. They tend to be a major site where white blood cells and the B and T lymphocytes can be located. This is what makes them essential to your immune system.

When a swollen occipital node is noted, it could mean that you have an infection or an illness. It is likely to occur when you have suffered a bacterial or viral infection. Swollen lymph node locations normally help the doctor establish the kind of infection that one could be suffering from.

It is likely for the occipital node to become painful as the nearby nerves start pressing the node. What causes swelling in your occipital lymph node?

1. The scalp of Head infections

A head infection is always the most obvious reason as to why your occipital nodes could be swollen. A node that is swollen will normally be tender to your touch and will feel as though it has been raised from the skin surface. Ringworms, lice, or dandruff may cause an infection.

2. STDs

When you mention sexually transmitted diseases, you have to include infections from syphilis, mononucleosis, and HIV. Inflamed nodes are commonly associated with these three infections. For instance, Mono targets nodes that are in your upper body and will normally cause them to start swelling. Mono is also known as the kissing disease, as it is commonly transmitted via an exchange of saliva.

3. Throat Infections

They are known to cause sore throats, discomfort, irritation, and difficulty swallowing. A throat infection can be accompanied by a patch on your tonsils, inflamed neck glands, and hoarseness when speaking. Infections in this area are often attributed to viruses and bacteria.

4. Tonsillitis

Tonsils are a kind of lymph nodes which can also easily become swollen. When these happen, the only solution is to have them removed. They are found near the top of your throat but at the back of your mouth.

They serve the same function as the other lymph nodes spread out all over the body and are crucial in assisting your body fight infections. Tonsils that have become swollen can make it difficult to swallow and may lead to fever, pain in the ears, and chills.

Behind Ears

An inflamed node occurring behind your ears could be caused by many varied factors, some of which tend to be more serious than the others. The lymph nodes, which, as mentioned earlier, are spread throughout your body, assists in storing fluids and nutrients, and also assist in the elimination of waste products.

Nodes behind your ears also assist in fighting damaging elements that could be in your blood, viruses, and bacteria. When the infection has successfully been eliminated from your body, the nodes absorb all the remaining elements and ensure that they are filtered out of the body immediately.

It is a process that can temporarily cause the lymph nodes to become swollen, though in such cases, they are not painful, and may even go unnoticed. Causes of swollen nodes behind your ears include:

1. Infections

Infections, e.g., bacteria that may be present in your mouth and fungal infection, can lead to nodes behind your ears becoming swollen. Given that they mainly help in fighting infections that have found their way into the body, they are constantly being exposed to all kinds of pathogens. Therefore, as they start to produce antibodies to assist in fighting off the infections, they begin to swell.

2. Injury

Damage to your neck or head region could cause the nodes in this region to begin to swell. The swelling will take place as the body is attempting to make repairs. A minor cut is enough to cause the body to start swelling due to the overproduction of antibodies.

3. Autoimmune diseases

When we mention autoimmune diseases, we are talking about conditions such as Hashimoto’s disease and lupus. The two conditions, among others, causes swelling in the nodes behind your ears because these diseases have already damaged the immune system in the body.

4. German Measles

It is caused by a virus known as rubella, and which manifests itself in the form of a pink or red rash appearing on your skin surface. Traditionally, the rash first appears on your face, and then slowly starts to work its way to the other sections of the body. Apart from the rash, you can also expect to notice inflamed nodes behind your ears.

Locations in armpits (axillary)

Inflammation in the armpits is also known as having armpit lumps. They come about when one of your nodes located under your armpits become inflamed or swollen. Swollen nodes vary, as some are small, while others could be noticeable upon close observation.

They could be caused by antiperspirant use, irritation caused by shaving, or cysts infections. But they may also indicate that one has a serious underlying medical condition. It is advisable to seek medical attention if you find that the lump is slowly becoming enlarged, is not painful or causing you any discomfort, and has refused to disappear.

Many of these lumps tend to be harmless and only come about when you have abnormal tissue growth. However, not all lumps are similar, as some could be related to a medical condition. You need to have a physician take a look at any unusual lumps that may have started to manifest. Common causes of these lumps include:

• Lupus
• Allergic reactions
• Leukemia
• An allergic reaction to a vaccination
• Lymphoma
• Breast cancer
• Fungal infections
• Viral or bacterial infections
• Lipomas

Diagnosis of swollen armpit nodes

A physical examination must first be conducted before a proper diagnosis of the armpit lump can be made. The doctor needs to make some inquiries on any changes that may have occurred in that lump, and whether you have been experiencing any pain. A massage will normally be used to establish the consistency and texture of any lump found under the armpits.

It is something that must exclusively be done using hands. There are instances where the physical exam will show that a lump is in no way harmful, e.g., benign lumps like those associated with lipomas. Such lumps will not require you to be treated as they will disappear on their own, though medication may be provided if a lump proves to be bothersome.

From the results of your physical examination, your doctor could find it necessary to order additional tests in a bid to rule out cancerous changes, allergic reactions, or infections. Some of the tests that may be ordered include:

• Allergy testing
• Complete blood count. It is used to establish the number of white and red blood cells that are currently present in the system.
• Biopsy
• Breast or chest X-ray

Lymph node locations in the neck (cervical)

Posterior cervical lymph nodes refer to the bundles of glands that are found in the cervical region of your spine or behind your neck. The glands which are a part of your immune system normally have white blood cells that scavenge your system for infections and then wade them off.

Lymphadenopathy or swollen cervical lymph nodes typically indicate that you may have an infection. This is because the nodes assist in filtering out harmful microorganisms and pathogens from your system.

Lymphatic tissue often takes the shape of a vessel or a node and then goes on to form the lymphatic system. Your neck region, combined with different areas of your body, normally have lymph nodes spread all over. Each node is responsible for a certain region. In the region where it has been deployed, it will need to deploy immune cells and provide assistance in the draining of fluids (lymphatic).

Given the role they play in your body, a doctor can pinpoint the location of infection by looking at the nodes. When you are suffering from a disease or have an infection, these nodes will normally start to release white blood cells into the system.

This is what causes the nodes to start swelling. Common causes of swollen posterior cervical lymph nodes include:

• An infection. Infections are often characterized by fever, congestion, and aches all over the body. Common infections that can cause your nodes to become swollen include:
  • Toxoplasmosis
  • Pharyngitis
  • Cytomegalovirus
  • Rubella
  • Periodontitis
  • Epstein-Barr virus
  • Mononucleosis
• Systemic causes. These include lupus, HIV, and rheumatoid arthritis
• Cancer
• Drugs and vaccines

In the back

Inflamed lymph nodes in your back indicate that one has a viral or bacterial infection. But the same nodes could also be an indication of cancer. Swollen lymph nodes in your back region mean that the nodes in the upper and lower section have started to malfunction. Some of the factors that could be causing this include:

Infection

As previously mentioned, infections are the leading cause of swollen lymph nodes. This is because the immune system attempts to fight back when it detects an infection in your body, and the release of the white blood cells causes the nodes to become inflamed. Mononucleosis is another known cause. It is a type of infection that occurs when one comes into contact with saliva that is infected.

Other known causes include:

• Lymphoma
• Tuberculosis
• Yaws
• Leukemia
• Lupus
• Rheumatoid arthritis
• Syphilis
• Skin infections
• AIDs
• Ear sores
• Tonsillitis

Symptoms accompanying swollen nodes in the back include:

• A sore throat
• Slight tenderness in affected lymph nodes
• Swelling of your muscles
• Rapid weight loss
• High fever
• Night Sweats
• A runny nose

Thoracic lymph nodes (chest)

Thoracic lymph nodes are normally divided into two main groups: parietal lymph nodes and visceral lymph nodes. The former is found in your thoracic walls, while the latter can be found in your internal organs. Due to the different lymph node locations, abnormalities occurring with the nodes located in the chest or thorax are not easy to identify.

But any variations in the number or size of a lymph node can easily indicate the presence of many pulmonary and extrapulmonary health conditions. To simplify the diagnosis process, the lymph nodes that are in the thorax section can further be broken down into some subcategories.

Lung lymph nodes are located in the bronchi, while the tracheobronchial and paratracheal groups are in the neck area. They can also be found in the junction linking the trachea and the bronchi. They are the ones that deal with the drainage coming from the lymph nodes, heart, thoracic trachea, bronchi, and lungs.

In the thoracic aorta, there is a group of nodes known as the posterior mediastinal nodes, which are closely associated with the tracheobronchial nodes, which drain into a person’s thoracic duct.  The lymph nodes in the chest wall are responsible for receiving drainage from the pectoral muscles, arms, and breasts.

In the stomach

According to Mayo Clinic, Lymphadenitis occurs when the nodes are inflamed. When this inflammation has an impact on the nodes that are in the membranes and the ones that connect your abdominal wall and bowel, then the condition is referred to as mesenteric lymphadenitis.

This condition is also known as mesenteric adenitis and often comes about when your intestines have become infected. It is a condition that mainly targets teenagers and children, and it has been known to mimic the signs that are associated with appendicitis.

But unlike appendicitis, this condition is not very serious, and it will normally clear on its own. Some of its known symptoms include:

• Fever
• Tenderness in the abdominal region
• Abdominal pain that is normally centered in the lower section

The symptoms can vary depending on what is behind this ailment. Other symptoms that you need to look for will include:

• A general feeling of being unwell
• Vomiting and nausea
• Diarrhea

What causes this condition?

The condition is normally caused by viral infections, e. g., gastroenteritis, also known as the stomach flu. It is an infection that has been known to cause thin tissues connecting the intestines to the abdominal wall to start becoming swollen.

Given that lymph nodes are spread all over the body, it means that the nodes that are closest to the infection site will become inflamed. Children have, for instance, been known to develop upper respiratory infections before getting this condition.

In the groin (inguinal lymph nodes)

Groin nodes are commonly known as inguinal nodes. Many people, especially men, normally avoid going to the doctor whenever the area is inflamed due to the sensitive nature of their location. In many cases, the swelling subsides without the need for any treatment, but in serious cases, there is a need for one to seek medical attention. The inguinal lymph nodes are located in the lower pelvic area and the upper part of your leg.

These nodes are in some cases as small as a pea, and other instances, as big as a small olive. You should also note that they tend to be shaped like a bean. Inguinal lymph nodes are in charge of filtering the lymphatic fluid that drains through the following:

What causes their inflammation?

Swelling in this area can be attributed to an injury that may have been sustained in this region. Normally, the inflammation will start to reduce as the affected region begins to heal. Be sure to contact your physician if you find that the swelling is not going down, or if it has been accompanied by other symptoms.

It is mainly caused by:

• Sexually transmitted diseases
• Allergic reactions
• Infections in the pelvic region, feet, or legs
• Cancer
• A hernia
• A reaction to drugs
• Benign cysts
• Fatty growths

Lymph nodes in legs

Exposure to viruses or bacteria has been known to cause swollen lymph nodes. As mentioned earlier, they assist in fighting infections by acting as filters. They trap bacteria and viruses before they can do any harm to your body.

There are situations where all you need to do is wait, and the swollen lymph nodes will heal on their own. However, you should note that the treatment method recommended by the physician will normally depend on what is causing this condition.

The most common causes are infections, e.g.,

• HIV
• Strep throat
• Skin infections
• Measles
• Mono
• Ear infections
• Infected tooth

Apart from the common infections, there are other uncommon infections, e.g.,

• Cat scratch fever
• Tuberculosis
• Sexually transmitted infections like syphilis

Immune system disorders that can cause this condition include:

• Rheumatoid arthritis—this is an inflammatory disease which targets the tissues lining your joints
• Lupus—another inflammatory disease targeting your lungs, joints, heart, skin, blood cells, and your kidneys.

Cancers that can cause this problem in your legs include:

• Lymphoma—this is cancer originating from your lymphatic system
• Leukemia—cancer of the blood which affects your lymphatic system and your bone marrow

Complications likely to occur if the swollen lymph nodes in your legs are not treated include:

• Infection of your bloodstream—any bacterial infection that could be present in the body may start progressing into sepsis—this takes place when the bloodstream has become overwhelmed by an infection. It can lead to organ failure and eventually, death.
• Abscess formation—abscesses are localized pus collections that have been brought about by an infection. Pus normally contains bacteria, dead tissue, and white blood cells. It must be drained as soon as possible.

In the knee

Popliteal lymph nodes comprise of between six and seven lymph nodes, which are found in your legs in the region close to your knees, and known as popliteal fossa. They are in charge of servicing the lower section of your legs and work on behalf of the lymphatic system.

These nodes come in two main sets, the superficial popliteal nodes, and the deep popliteal nodes. Lateral superficial trunks inside your legs are responsible for feeding these lymph nodes.

In a popliteal node, there is a fibrous outer capsule, which usually encloses your lymphatic tissue and is responsible for filtering and balancing out the blood being supplied to your lower extremities.

What is the role of lymph nodes?

The lymph nodes, which are a part of the lymphatic system, have the following functions:

• Fight infections and raise an immune reaction. The lymph nodes tend to be overactive when the body is fighting. In this case, they will swell up in a bid to deal with the infection.
• Filtering blood—the spleen is part of the lymphatic system and is in charge of filtering blood. It deals with all viruses, bacteria, and other unwanted particles.
• Draining blood into the tissues from the bloodstream—blood circulation through channels that are quite narrow often leads to plasms and fluids, that are carrying nutrients and oxygen leaking into tissues. They thus end up transporting the waste materials that are in these tissues and taking them into your lymphatic system.
• Filtering lymph at the nodes—lymph nodes have white blood cells that can attack any virus or bacteria that finds its way into the nodes.

It is important to note that if the swelling in the lymph nodes has been caused by a bacterial infection that has not been treated, it could end up spreading to your bloodstream, and this may pose serious complications later.

References:

http://www.bartleby.com/107/179.html

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Stages of Breast Cancer | Understand Breast Cancer Staging

After someone is diagnosed with breast cancer, doctors will try to figure out if it has spread, and if so, how far. This process is called staging. The stage of a cancer describes how much cancer is in the body. It helps determine how serious the cancer is and how best to treat it. Doctors also use a cancer’s stage when talking about survival statistics.

The earliest stage breast cancers are stage 0 (carcinoma in situ). It then ranges from stage I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter means a lower stage.

How is the stage determined?

The staging system most often used for breast cancer is the American Joint Committee on Cancer (AJCC) TNM system. The most recent AJCC system, effective January 2018, has both clinical and pathologic staging systems for breast cancer:

• The pathologic stage (also called the surgical stage) is determined by examining tissue removed during an operation.
• Sometimes, if surgery is not possible right away or at all, the cancer will be given a clinical stage instead. This is based on the results of a physical exam, biopsy, and imaging tests. The clinical stage is used to help plan treatment. Sometimes, though, the cancer has spread further than the clinical stage estimates, and may not predict the patient’s outlook as accurately as a pathologic stage.

In both staging systems, 7 key pieces of information are used:

• The extent (size) of the tumor (T): How large is the cancer?  Has it grown into nearby areas?
• The spread to nearby lymph nodes (N): Has the cancer spread to nearby lymph nodes? If so, how many?
• The spread (metastasis) to distant sites (M): Has the cancer spread to distant organs such as the lungs or liver?
• Estrogen Receptor (ER) status: Does the cancer have the protein called an estrogen receptor?
• Progesterone Receptor (PR) status: Does the cancer have the protein called a progesterone receptor?
• Her2 status: Does the cancer make too much of a protein called Her2?
• Grade of the cancer (G): How much do the cancer cells look like normal cells?

In addition, Oncotype Dx® Recurrence Score results may also be considered in the stage in certain circumstances.

Once all of these factors have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more information see Cancer Staging.

Details about the first three factors (the TNM categories) are below. However, the addition of information about ER, PR, and Her2 status along with grade has made stage grouping for breast cancer more complex than for other cancers. Because of this, it is best to ask your doctor about your specific stage and what it means.

Details of the TNM staging system

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. The categories below use the pathologic (surgical) definitions.

T categories for breast cancer

T followed by a number from 0 to 4 describes the main (primary) tumor’s size and if it has spread to the skin or to the chest wall under the breast. Higher T numbers mean a larger tumor and/or wider spread to tissues near the breast.

TX: Primary tumor cannot be assessed.

T0: No evidence of primary tumor.

Tis: Carcinoma in situ (DCIS, or Paget disease of the breast with no associated tumor mass)

T1 (includes T1a, T1b, and T1c): Tumor is 2 cm (3/4 of an inch) or less across.

T2: Tumor is more than 2 cm but not more than 5 cm (2 inches) across.

T3: Tumor is more than 5 cm across.

T4 (includes T4a, T4b, T4c, and T4d): Tumor of any size growing into the chest wall or skin. This includes inflammatory breast cancer.

N categories for breast cancer

N followed by a number from 0 to 3 indicates whether the cancer has spread to lymph nodes near the breast and, if so, how many lymph nodes are involved.

Lymph node staging for breast cancer is based on how the nodes look under the microscope, and has changed as technology has improved. Newer methods have made it possible to find smaller and smaller collections of cancer cells, but experts haven’t been sure how much these tiny deposits of cancer cells affect outlook.

It’s not yet clear how much cancer in the lymph node is needed to see a change in outlook or treatment. This is still being studied, but for now, a deposit of cancer cells must contain at least 200 cells or be at least 0.2 mm across (less than 1/100 of an inch) for it to change the N stage. An area of cancer spread that is smaller than 0.2 mm (or fewer than 200 cells) doesn’t change the stage, but is recorded with abbreviations (i+ or mol+) that indicate the type of special test used to find the spread.

If the area of cancer spread is at least 0.2 mm (or 200 cells), but still not larger than 2 mm, it is called a micrometastasis (one mm is about the size of the width of a grain of rice). Micrometastases are counted only if there aren’t any larger areas of cancer spread. Areas of cancer spread larger than 2 mm are known to affect outlook and do change the N stage. These larger areas are sometimes called macrometastases, but are more often just called metastases.

NX: Nearby lymph nodes cannot be assessed (for example, if they were removed previously).

N0: Cancer has not spread to nearby lymph nodes.

N0(i+): The area of cancer spread contains fewer than 200 cells and is smaller than 0.2 mm. The abbreviation “i+” means that a small number of cancer cells (called isolated tumor cells) were seen in routine stains or when a special type of staining technique, called immunohistochemistry, was used.

N0(mol+): Cancer cells cannot be seen in underarm lymph nodes (even using special stains), but traces of cancer cells were detected using a technique called RT-PCR. RT-PCR is a molecular test that can find very small numbers of cancer cells. (This test is not often used to find breast cancer cells in lymph nodes because the results do not influence treatment decisions.)

N1: Cancer has spread to 1 to 3 axillary (underarm) lymph node(s), and/or tiny amounts of cancer are found in internal mammary lymph nodes (those near the breast bone) on sentinel lymph node biopsy.

N1mi: Micrometastases (tiny areas of cancer spread) in the lymph nodes under the arm. The areas of cancer spread in the lymph nodes are at least 0.2mm across, but not larger than 2mm.

N1a: Cancer has spread to 1 to 3 lymph nodes under the arm with at least one area of cancer spread greater than 2 mm across.

N1b: Cancer has spread to internal mammary lymph nodes on the same side as the cancer, but this spread could only be found on sentinel lymph node biopsy (it did not cause the lymph nodes to become enlarged).

N1c: Both N1a and N1b apply.

N2: Cancer has spread to 4 to 9 lymph nodes under the arm, or cancer has enlarged the internal mammary lymph nodes

N2a: Cancer has spread to 4 to 9 lymph nodes under the arm, with at least one area of cancer spread larger than 2 mm.

N2b: Cancer has spread to one or more internal mammary lymph nodes, causing them to become enlarged.

N3: Any of the following:

N3a: either:

Cancer has spread to 10 or more axillary lymph nodes, with at least one area of cancer spread greater than 2 mm,

OR

Cancer has spread to the lymph nodes under the collarbone (infraclavicular nodes), with at least one area of cancer spread greater than 2 mm.

N3b: either:

Cancer is found in at least one axillary lymph node (with at least one area of cancer spread greater than 2 mm) and has enlarged the internal mammary lymph nodes,

OR

Cancer has spread to 4 or more axillary lymph nodes (with at least one area of cancer spread greater than 2 mm), and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.

N3c: Cancer has spread to the lymph nodes above the collarbone (supraclavicular nodes) with at least one area of cancer spread greater than 2 mm.

M categories for breast cancer

M followed by a 0 or 1 indicates whether the cancer has spread to distant organs — for example, the lungs, liver, or bones.

M0: No distant spread is found on x-rays (or other imaging tests) or by physical exam.

cM0(i+): Small numbers of cancer cells are found in blood or bone marrow (found only by special tests), or tiny areas of cancer spread (no larger than 0.2 mm) are found in lymph nodes away from the underarm, collarbone, or internal mammary areas.

M1: Cancer has spread to distant organs (most often to the bones, lungs, brain, or liver).

Examples using the full staging system

Because there are so many factors that go into stage grouping for breast cancer, it’s not possible to describe here every combination that might be included in each stage. The many different possible combinations mean that two women who have the same stage of breast cancer might have different factors that make up their stage.

Here are 3 examples of how all of the factors listed above are used to determine the pathologic (surgical) breast cancer stage:

Example #1

If the cancer size is between 2 and 5 cm (T2) but it has not spread to the nearby lymph nodes (N0) or to distant organs (M0) AND is:

• Grade 3
• Her2 negative
• ER positive
• PR positive

The cancer stage is IB.  

Example #2

If the cancer is larger than 5 cm (T3) and has spread to 4 to 9 lymph nodes under the arm or to any internal mammary lymph nodes (N2) but not to distant organs (M0) AND is:

• Grade 2
• Her2 positive
• ER positive
• PR positive

The cancer stage is IB.
 

Example #3

If the cancer is larger than 5 cm (T3) and has spread to 4 to 9 lymph nodes under the arm or to any internal mammary lymph nodes (N2) but not to distant organs (M0) AND is:

• Grade 2
• Her2 negative
• ER negative
• PR negative

The cancer stage is IIIB. 

These are only 3 examples out of many possible combinations of factors. To understand what your breast cancer stage is, and what it means, talk to your doctor.

Mediastinal mass

Department of Thoracic Surgery No. 1

Neoplasms of the mediastinum (tumors and cysts) in the structure of all oncological diseases make up 3-7%. Most often, neoplasms of the mediastinum are detected in people 20-40 years old, that is, in the most socially active part of the population. About 80% of the detected neoplasms of the mediastinum are benign, and 20% are malignant.

Classification

Mediastinal neoplasms originate from dissimilar tissues and are united by only one anatomical boundaries.These include not only true tumors, but also cysts and tumor-like formations of different localization, origin and course. All neoplasms of the mediastinum, according to their source of origin, can be divided into the following groups:
1. Primary neoplasms of the mediastinum.
2. Secondary malignant tumors of the mediastinum (metastases of malignant tumors of organs located outside the mediastinum, to the lymph nodes of the mediastinum).
3. Tumors of the mediastinal organs (esophagus, trachea, pericardium, thoracic lymphatic duct).
4. Tumors from tissues limiting the mediastinum (pleura, sternum, diaphragm).
5. Pseudo-tumor diseases (lesions of lymph nodes in tuberculosis, Benier-Beck-Shaumyan disease, parasitic cysts, aneurysms and malformations of large vessels, limited inflammatory processes and some others).

Primary neoplasms of the mediastinum include tumors and cysts that developed from tissues that are embryogenetically inherent in the mediastinal space, or from aberrant tissues that have shifted into the mediastinum when embryogenesis is disturbed.The concept of primary neoplasms of the mediastinum includes dozens of different (by origin, histogenesis, growth pattern) tumors and cysts located in different parts of the mediastinum.
During the course of the disease with neoplasms of the mediastinum, an asymptomatic period and a period of pronounced clinical manifestations can be distinguished. The duration of the asymptomatic period depends on the location and size of the neoplasm, its nature (malignant, benign), growth rate, relationship with the organs and formations of the mediastinum.Very often, neoplasms of the mediastinum are asymptomatic for a long time, and they are accidentally discovered during a preventive X-ray examination of the chest. The most common symptoms are pain arising from compression or growth of a tumor into the nerve trunks or nerve plexuses, which is possible in both benign and malignant neoplasms of the mediastinum. The pain, as a rule, is not intense, localized on the side of the lesion, and often radiates to the shoulder, neck, interscapular region.Left-sided pains are often similar to angina pain. If bone pain occurs, metastases should be suspected. Compression or germination of the borderline sympathetic trunk by a tumor causes the appearance of a syndrome characterized by drooping of the upper eyelid, dilated pupil and retraction of the eyeball on the affected side, impaired sweating, changes in local temperature and dermographism. The defeat of the recurrent laryngeal nerve is manifested by the hoarseness of the voice, the phrenic nerve – by the high standing of the dome of the diaphragm.Spinal cord compression leads to dysfunction of the spinal cord.
A manifestation of the compression syndrome is the compression of large venous trunks and, first of all, the superior vena cava (superior vena cava syndrome). It is manifested by a violation of the outflow of venous blood from the head and upper half of the body: patients have noise and heaviness in the head, aggravated in an inclined position, chest pain, shortness of breath, swelling and cyanosis of the face, upper half of the body, swelling of the veins of the neck and chest.Central venous pressure rises to 300-400 mm of water. Art. When the trachea and large bronchi are compressed, coughing and shortness of breath occur. Compression of the esophagus can cause dysphagia – a disruption in the passage of food.

At the later stages of the development of neoplasms, there are: general weakness, fever, sweating ,. weight loss, which are characteristic of malignant tumors. In some patients, manifestations of disorders associated with intoxication of the body with products secreted by growing tumors are observed.These include arthralgic syndrome, reminiscent of rheumatoid arthritis; pain and swelling of the joints. swelling of the soft tissues of the extremities, an increase in heart rate, an abnormal heart rhythm. Thus, the clinical signs of neoplasms, the mediastinum are very diverse, but they appear in the late stages of the development of the disease and do not always allow us to establish an accurate etiological and topographic anatomical diagnosis.

Diagnostics:

Treatment:

Diagnostic surgical interventions using endovidiosurgical technologies.
Operations aimed at removing formations, including using endovidiosurgical technologies.

Branch services and prices

National Medical Research Center of Oncology named after V.I. N.N. Blokhin

Operations for malignant neoplasms of various localization involve the removal of a single block of the affected organ and tissue with lymph nodes in the areas of regional metastasis.

Along with the therapeutic effect, performing lymphadenectomy makes it possible to clarify the stage of the disease, which is one of the main criteria for the prognosis and planning of additional treatment.At the same time, the removal of tissue from the lymph nodes significantly increases the number of complications. Based on the foregoing, it is clear that surgeons strive to perform lymphadenectomy not prophylactically, but according to indications, i.e. in the presence of metastases in the lymph nodes.

Modern research methods (echography, computed and magnetic resonance imaging, radionuclide diagnostics) cannot give a clear answer about the presence or absence of metastases in the lymph nodes.The only reliable and significant method for diagnosing lymphogenous metastasis is a morphological examination of the lymph nodes.

In this regard, R.M. Cabanas in 1977 put forward the concept of the so-called sentinel lymph node (SLN), which primarily carries out the outflow of lymph from the affected area. The node is a kind of filter for tumor cells, the first to be affected by metastases. To search for sentinel lymph nodes J.C. Alex and D.N. Krag used a radioisotope method to identify sentinel lymph nodes using a portable gamma scanner. In this form, the method has been applied to the present day. Since then, in many clinics in Europe and the United States, the method has found wide application in tumors of various localization to resolve the issue of the volume of lymphadenectomy, mainly in patients with skin melanoma and breast cancer.

To determine the possible pathways of lymphogenous metastasis and sentinel lymph nodes using the radioisotope method, on the eve of the operation, a lymphotropic radiopharmaceutical is administered to the patient along the tumor perimeter, which selectively penetrates the lymphatic capillaries, reaches the lymph nodes and accumulates in them.Assessment of the condition of regional lymphatic collectors and the search for sentinel lymph nodes is performed by means of plain scintigraphy, using a gamma camera before surgery and using a portable gamma scanner during surgery. Lymph nodes are removed and examined outside the surgical field. If, as a result of an urgent histological examination, a metastatic lesion of the sentinel node is not detected, as a rule, there is no need for radical lymph node dissection.

Marking of RFP hyperfixation foci on the skin with a permanent marker under the detectors of the gamma camera (a). Intraoperative search for SLNs using a gamma sensor (b).

Hybrid tomograms in axial (a), sagittal (b) and frontal (c) projections of the chest of a patient with breast cancer with 99mTc-labeled nanocolloid. The site of RP injection into the right mammary gland (white arrow), as well as 2 lesions corresponding to the SLN, located in the right axillary region (red arrows), are determined.SPECT / CT helped to establish the exact anatomical localization of the SLN.

Tomograms in axial (a, b, c) and frontal (d, e, f) projections of a patient diagnosed with melanoma of the skin of the anterior abdominal wall with labeled nanocolloid ^{99 m} Tc. The SLN is visualized in the right and left groin areas. An example of cross-flow lymph flow.

Lymph node biopsy – where to make a lymph node biopsy near the Slavyansky Boulevard metro station, prices, indications for the procedure

Lymph nodes are part of the human immune system, and white blood cells are produced in them to fight infection.They are able to respond to the presence of a viral, bacterial infection, cancer process.

Accordingly, an increase in lymph nodes can be associated with an inflammatory or cancerous process. The main research method in this situation is biopsy. Puncture can be performed in the armpits, groin, behind the ears, lower jaw, neck.

There are two main types of lymph node biopsy:

• Puncture: fine-needle and trephine biopsy, which differ in the type of needles;
• An open biopsy performed under general anesthesia and removing the entire nodule.

Depending on the type and location of the study, the procedure can take from ten minutes to one hour. After receiving the material, he is sent to the laboratory of the Kutuzovsky Medical Center for cytology and histology.

Cancer, primarily formed in the lymph nodes, most often occurs in young people.

Main indications for biopsy

Lymph node biopsy is prescribed according to the main indications:

• The presence of fluid in the assembly, confirmed by ultrasonic data;
• A single enlargement of the lymph node, not accompanied by the formation of conglomerates.Such solitary enlargements are most often characteristic of metastatic lesions;
• The need to obtain more material when cytological and histological studies have already been carried out, for example, for molecular diagnostics.

Why is a biopsy done?

When prescribing a biopsy, the specialist wants to find out the cause of the enlarged lymph node. The main reasons for the appointment of the procedure:

• The likelihood of developing a tumor that the doctor may suspect from clinical data;
• Prolonged lymphadenopathy, the cause of which cannot be determined;
• Correction of treatment, including anti-cancer treatment.

Doctors have several opinions about the size of the lymph nodes to be examined. Some specialists carry out this procedure even for knots less than one centimeter in size. However, in the presence of at least one node, more than three centimeters in size, that has no connection with the infectious process, it is an indication for a biopsy.

A situation where a second biopsy is required is quite common. Most often these are changes identified during histology.Lymph nodes for biopsy are selected according to the following characteristics:

• Size – select the largest;
• The term of its increase – recently increased is suitable for biopsy;
• If there are several such nodes, then the zone of their existence is selected.