Intrathymic epidermoid cyst: a very rare condition.

A 65-year-old man presented with a nonspecific thymic neoplasm following blunt thoracic trauma. The lesion increased in size over 12 years, to reach 47 mm in diameter. After thymectomy, the lesion was described as an epidermoid lining cyst composed of thickened stratified squamous epithelium. We assume that this rare pathological condition was caused by skin tissue islands and fat migrating into the mediastinum.