Primary Mediastinal B-Cell Lymphoma Presenting as Cardiac Tamponade.

Primary mediastinal B-cell lymphoma (PMBCL) is a rare subtype of non-Hodgkin lymphoma. Typical symptoms include cough, chest pain, and dyspnea; however, cardiac tamponade as the primary manifestation is exceedingly rare. We hereby present a case of a 34-year-old male with a past medical history of obesity, who presented to our emergency department with a chronic dry cough for 4 months. On admission, computed tomography demonstrated a large 11.1-cm diameter anterior mediastinal mass, and echocardiography demonstrated cardiac tamponade physiology. The patient underwent further workup including pericardiocentesis, subsequent pericardial window, and mediastinal biopsy, which demonstrated histopathology consistent with PMBCL. Our case highlights the importance of a complete and thorough workup for patients with chronic untraditional symptoms. This case is unique in that PMBCL is rarely associated with cardiac tamponade as the primary clinical presentation. Additionally, we recommend an extensive cardiac workup for patients presenting with a large mediastinal mass, as failure to do so may result in patient morbidity and mortality.