What are the causes of mediastinal lymphadenopathy (enlargement of lymph nodes in the mediastinum)?

From the Guidelines

Mediastinal lymphadenopathy should be evaluated using a combination of imaging studies, such as CT and PET scans, and tissue sampling through techniques like endobronchial ultrasound-guided biopsy or mediastinoscopy, to determine the underlying cause and guide treatment. The diagnosis and management of mediastinal lymphadenopathy depend on the underlying condition, which can range from infections to malignancies. According to the study by 1, the European Society for Medical Oncology (ESMO) recommends a staging algorithm for non-small-cell lung cancer (NSCLC) that includes imaging studies and tissue sampling to determine the presence of mediastinal lymph node involvement.

The study by 1 highlights the importance of differentiating between NSCLC and small cell lung cancer (SCLC), as the diagnosis and treatment approaches differ significantly. The American College of Chest Physicians (ACCP) guidelines recommend a diagnostic approach that includes imaging studies, such as CT and PET scans, and tissue sampling through techniques like bronchoscopy and mediastinoscopy.

In terms of staging, the study by 1 emphasizes the importance of defining malignant involvement of the mediastinal lymph nodes, as this determines whether there is surgically resectable disease. The study also highlights the role of imaging studies, such as CT scans, in evaluating the mediastinum and determining the need for invasive staging tests.

The study by 1 provides guidance on reporting incidental findings on thoracic CT scans, including mediastinal lymphadenopathy. The study recommends considering the size, texture, and density of the lymph nodes, as well as the presence of other findings, such as pulmonary disease or cardiovascular disease.

The study by 1 also provides guidance on managing incidental findings on thoracic CT scans, including mediastinal masses. The study recommends localizing the mass to a mediastinal compartment and assessing features such as density, internal components, enhancement, and behavior to guide management.

Key points to consider in the evaluation and management of mediastinal lymphadenopathy include:

• The use of imaging studies, such as CT and PET scans, to evaluate the mediastinum and determine the presence of lymph node involvement
• The importance of tissue sampling through techniques like endobronchial ultrasound-guided biopsy or mediastinoscopy to determine the underlying cause
• The role of staging in determining the presence of surgically resectable disease
• The consideration of other findings, such as pulmonary disease or cardiovascular disease, in the evaluation and management of mediastinal lymphadenopathy
• The importance of localizing mediastinal masses to a compartment and assessing features such as density, internal components, enhancement, and behavior to guide management.

From the Research

Definition and Causes of Mediastinal Lymphadenopathy

• Mediastinal lymphadenopathy refers to the enlargement of lymph nodes in the mediastinum, which can be caused by various benign and malignant conditions 2.
• The most common causes of mediastinal lymphadenopathy include malignancy (lung cancer, lymphoma, and extrathoracic cancer) and granulomatous conditions (sarcoidosis and tuberculosis) 2.

Diagnosis of Mediastinal Lymphadenopathy

• The initial clue to the presence of enlarged mediastinal lymph nodes is often through thoracic imaging modalities 2.
• Endosonographic modalities such as endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) have emerged as a crucial tool in the diagnosis of mediastinal lymphadenopathy, offering a minimally invasive alternative for cytodiagnosis in the mediastinum 3.
• A tissue diagnosis is essential for accurate diagnosis and optimal management, and selecting the appropriate tissue diagnosis modality is crucial 2.

Treatment of Mediastinal Lymphadenopathy

• The treatment of primary mediastinal large B-cell lymphoma (PMLBCL) is a subject of ongoing debate, with no accepted standard of care 4, 5.
• Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) with or without radiotherapy has been shown to be effective in treating PMLBCL, but the need for more aggressive treatment strategies is still questionable 4.
• A dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine and prednisone plus rituximab (DA-EPOCH-R) regimen has been evaluated in children and adolescents with PMLBCL, but did not improve event-free survival compared to historical controls 6.

Diagnostic Approaches

• EUS-FNA has been shown to be a safe and effective diagnostic tool for mediastinal lymphadenopathy, with high sensitivity, specificity, and diagnostic accuracy 3.
• The choice of diagnostic modality depends on the individual patient's characteristics and the suspected underlying cause of the mediastinal lymphadenopathy 2.