Epidermoid cyst-a rare mediastinal mass.

A 39-year-old male was referred to our service for treatment of an asymptomatic mediastinal mass. The mass was detected on a routine pre-employment chest X-ray. CT scan showed a well-defined soft tissue mass measuring 7.5 × 5.5 × 5.3 cm in close relation to the right border of the heart. A CT-guided biopsy proved to be inconclusive as necrotic tissue was obtained. At exploratory thoracotomy, a well-defined cyst was found attached to the right side of the pericardium. The cyst was totally excised and sent for histopathological examination which came back with a surprise diagnosis of epidermoid cyst.