A Rare Case of a High-Grade Thymic Squamous Cell Carcinoma Presenting as Cardiac Tamponade

Thymic tumors (for example, thymomas, thymic carcinomas, and thymic neuroendocrine tumors) are rare tumors. Thymic carcinomas are aggressive thymic epithelial neoplasms with a poor prognosis. Cardiac tamponade as a presenting complaint of malignant thymic carcinoma is rare. A 64-year-old woman presented to the emergency department with complaints of progressive exertional dyspnea and chest discomfort. On physical examination, she had diminished breath sounds at the left lung base. The chest x-ray showed a mediastinal widening, significant cardiomegaly, and pleural effusion. CT scan of the chest revealed a dominant mediastinal mass, left-sided pleural effusion, and pericardial effusion. Transthoracic echocardiogram showed 3 cm circumferential pericardial effusion, with evidence of cardiac tamponade. An emergent pericardiocentesis and thoracentesis were done. A core needle biopsy of the mediastinal mass revealed a high-grade non-keratinizing squamous cell thymic carcinoma. Immunohistochemistry staining was positive for pan-cytokeratin, high molecular weight cytokeratin, CK 5/6, E-cadherin, p63, epithelial membrane antigen (EMA), and BerEp4. The patient had repeated hospital admissions due to recurrent malignant pericardial effusion and left pleural effusion. The patient was planned for radiation and chemotherapy with oncology. In our review of literature, the primary squamous cell thymic carcinoma presenting initially as a cardiac tamponade was found to be a rare event. Early diagnosis and treatment are of utmost importance given the aggressive clinical course culminating in to poor outcome.