[Familial thymoma].

The case reports are presented of two siblings with familial thymoma. The thymomas developed at the same age in both siblings. The tumours were removed by thoracotomy and classified histologically as identical thymic squamous cell carcinomas. The brother is still alive and well four years after treatment; the sister died of pulmonary embolism, but without residual or recurrent mediastinal mass, one year after surgery. Familial thymomas are very rare. This is the first report of a familial squamous cell carcinoma of thymus. The problem of classification and malignancy of thymomas are discussed.