mediastinal lymphadenopathy mediastinal lymphadenopathy mediastinal lymphadenopathy or mediastinal adenopathy is an enlargement of the mediastinal lymph nodes. micrograph of a primary mediastinal large b-cell lymphoma, a cause of mediastinal lymphadenopathy. h&e stain. causes there are many possible causes of mediastinal lymphadenopathy, including: tuberculosis sarcoidosis lung cancer/oesophageal cancer lymphangitis carcinomatosa cystic fibrosis histoplasmosis acute lymphoblastic leukemia coccidioidomycosis lymphoma whipple's disease goodpasture syndrome hypersensitivity pneumonitis inflammatory response to silicone (leaked from ruptured implants) which has migrated and collected in mediastinal lymph nodes. silicone mediastinal lymphadenopathy.