Xanthomas are benign soft-tissue lesions commonly occurring on the skin, subcutis, or tendon sheaths of patients. The lung and thoracic cavity is a rare location for xanthomas. We present a 39-year-old woman who was admitted to our hospital with complaints of dyspnea, cough, and chest pain. She had a prior diagnosis of type II familial hypercholesterolemia. Chest x-ray film and computed tomography scans revealed a large tumor-like mass in the right hemithorax. Thoracal mass and narrowed tracheal segments were removed using cardiopulmonary bypass. Histopathologic findings were consistent with xanthoma.