An unusual cause of recurrent syncope: Mediastinal lymphoma diagnosed with transesophageal echocardiography.

Non-Hodgkin's lymphoma (NHL) rarely presents initially with cardiac symptoms. In this case, its first symptom was a recurrent syncope. The diagnosis of mediastinal tumor was made with transesophageal echocardiography. Considerable compression of the left atrium and superior vena cava without intracardiac growth was a cause of the syncope. Tumor biopsy revealed a diffuse, high-grade, large B-cell NHL. The patient died after four cycles of chemotherapy. To our knowledge, no previous report has demonstrated a syncope as an initial presentation of mediastinal lymphoma not invading the heart.