[Primary thymic carcinomas. Three cases and a review of the literature].

Thymic carcinoma is a very rare malignancy. In 1999, a World Health Organization committee published histologic criteria for distinct thymoma entities (labelled as type A, AB, B1, B2, B3 thymomas) and for the heterogeneous group of thymic carcinomas, collectively called type C tumour. Thymic carcinoma differs from thymoma in that it displays cytologically malignant features, extensive local invasion, and a substantial potential for metastasis. It constitutes a heterogeneous group of tumours that display different biological behaviours and prognoses. The majority of thymic carcinomas are either squamous carcinomas or lymphoepithelioma-like carcinomas. This study included three male patients aged 20, 46 and 19years respectively with histologically proven thymic carcinoma diagnosed at the author's institution. All of the patients presented a large mass of the anterior mediastinum. Histological examination of the different tumours revealed three distinct variants of thymic carcinoma, namely: epidermoid carcinoma, clear cell carcinoma and lymphoepithelioma-like carcinoma.