Mediastinal Lymphadenopathy
Mediastinal lymphadenopathy refers to enlargement of lymph nodes in the mediastinum, the central area of the chest between the lungs. Lymph nodes are small structures that filter lymphatic fluid and are an important part of the immune system. Enlargement can occur from a wide range of conditions, including infections, inflammatory and autoimmune diseases, lymphoma, and metastatic cancer. CT of the chest is the primary imaging test used to identify enlarged mediastinal lymph nodes and to help guide further evaluation.
What is it?
The mediastinum is the central compartment of the chest that lies between the lungs and contains the heart, great vessels, trachea, esophagus, thymus, nerves, and many groups of lymph nodes. Lymph nodes throughout the body act as filters for lymphatic fluid and help the immune system respond to infections and other challenges. Mediastinal lymphadenopathy refers to enlargement of one or more of these chest lymph nodes, which radiologists typically identify when nodes exceed a certain size or appear abnormal in shape, density, or pattern on imaging.
Mediastinal lymphadenopathy can result from many different conditions, which can be loosely grouped into a few categories. Infectious causes include reactive enlargement from common respiratory infections, tuberculosis, fungal infections (such as histoplasmosis or coccidioidomycosis in endemic regions), bacterial infections, and viral illnesses. Inflammatory and autoimmune conditions—most notably sarcoidosis, but also others such as IgG4-related disease and certain connective tissue disorders—can produce characteristic patterns of node enlargement. Malignant causes include lymphoma (both Hodgkin and non-Hodgkin), metastatic spread from primary lung cancer or cancers elsewhere in the body (such as breast, head and neck, gastrointestinal, and genitourinary cancers), and other less common malignancies. Some lymph nodes may be enlarged simply due to age-related changes or chronic exposures, such as long-term smoking or environmental dust.
Symptoms depend on the underlying cause, the size and location of the enlarged nodes, and whether they are pressing on nearby structures. Many cases of mediastinal lymphadenopathy cause no symptoms and are discovered incidentally on chest imaging. When symptoms occur, they may include cough, chest discomfort, shortness of breath, hoarseness (from involvement of the recurrent laryngeal nerve), difficulty swallowing, or, in larger nodes pressing on major veins, facial or upper-extremity swelling (superior vena cava syndrome). Systemic symptoms such as fever, night sweats, fatigue, and unintended weight loss—sometimes called “B symptoms”—are particularly important to recognize because they can suggest lymphoma or other serious underlying conditions. Symptoms of an active infection or autoimmune disease may also be present.
CT of the chest with intravenous contrast is the primary imaging test for evaluating mediastinal lymphadenopathy because it provides detailed information about node size, distribution, shape, density (including calcification), and relationship to nearby structures. Imaging features and distribution patterns often suggest more likely causes; for example, certain patterns are characteristic of sarcoidosis, while others raise concern for lymphoma or metastasis. PET/CT can help assess metabolic activity of the nodes and identify additional sites of disease. When the cause remains uncertain or when malignancy is suspected, tissue sampling—often through endobronchial ultrasound-guided biopsy (EBUS), mediastinoscopy, or image-guided biopsy—is performed to establish a definitive diagnosis. Laboratory testing and additional imaging may also play a role.
Important to Know
Evaluation and treatment of mediastinal lymphadenopathy are individualized and depend on the suspected cause, the patient’s symptoms, medical history (including infections, prior cancers, autoimmune disease, and exposures), and the imaging pattern. Care is often coordinated by a multidisciplinary team that may include primary care, pulmonology, infectious disease, rheumatology, oncology, thoracic surgery, and interventional radiology.
In some cases—particularly when the imaging features and clinical picture suggest a transient or reactive cause—observation with follow-up imaging may be appropriate. In other cases, prompt biopsy is needed to confirm a diagnosis such as lymphoma, sarcoidosis, infection, or metastatic cancer, and to guide treatment. Treatment of the underlying condition (for example, antibiotics for bacterial infection, antimycobacterial therapy for tuberculosis, immunosuppressive treatment for autoimmune disease, or chemotherapy for lymphoma) typically resolves or reduces the lymph node enlargement over time.
Because mediastinal lymph nodes can enlarge for many different reasons—and the implications range widely—imaging findings are always interpreted alongside the patient’s symptoms, exposures, and broader clinical context rather than in isolation.
Red flag symptoms include rapidly worsening shortness of breath, severe chest pain, facial or upper-extremity swelling, hoarseness, difficulty swallowing, coughing up blood, persistent unexplained fever or night sweats, or significant unintended weight loss. These warrant prompt medical evaluation.