Thymic carcinoma with glandular differentiation arising in a congenital thymic cyst.

A case of thymic carcinoma with glandular differentiation arising in congenital thymic cyst in a 50-year-old male is reported. Neoplasia in congenital thymic cyst is a rare phenomenon and is seldom associated with glandular differentiation. It is important to differentiate these neoplasms from carcinomas of the lower respiratory tract and from thymic carcinomas with secondary cystic degeneration, in view of their relatively good prognosis and the therapeutic implications.