Unusual cardiac paraganglioma mimicking an atypical carcinoid tumor of the lung.

We present a case of unusual cardiac paraganglioma (PG) initially misdiagnosed as atypical carcinoid tumor of the lung and discuss key clinical and pathologic characteristics that guide surgical management of these rare chromaffin cell tumors. A 64-year-old female with persistent cough and back pain was found to have a 4 cm × 3 cm mass abutting multiple cardiopulmonary structures. A biopsy was performed at an outside institution and pathology reported "atypical neuroendocrine carcinoma, consistent with carcinoid". The patient was transferred to our institution and pericardial resection with right pneumonectomy was performed to excise the tumor. Histology of the mass was that of PG with multiple ethanol embolizations. Immunohistochemical examination revealed that type I (chief) cells were positive for neuroendocrine markers (chromogranin A and synaptophysin), while type II (sustentacular) cells were positive for S100. There was no evidence of atypical carcinoid tumor in the lung. PG is an entity of chromaffin cell tumors that often affects the adrenal glands and carotid body. PG rarely occurs in the thoracic region, accounting for just 1-2% of all PG. Proper diagnosis of cardiac PG is challenging owing to its rare prevalence, subtle symptoms of presentation, and the neuroendocrine histopathological features it shares with atypical carcinoids. These tumors are typically benign and are best treated by surgical resection. Our report examines the approach to appropriate diagnosis of cardiac PG vs. atypical carcinoid, preoperative management, and surgical treatment by describing successful resection through thoracotomy without the use of cardiopulmonary bypass.