Thymic adenocarcinoma of the mediastinum is extremely rare. Only 12 cases adenocarcinoma associated with a thymic cyst have been reported in the literature. In this report, we describe a case of a thymic adenocarcinoma associated with thymic cyst. A 70-year-old man, presented with two months of chest tightness, breath shortness and chest pain. The contrast enhanced CT scan of chest revealed a round, cystic mass in right anterior mediastinum. Microscopic examination revealed that the lining consisted of flat to cuboidal and columnar epithelium and adenocarcinoma infiltrated into the thymic tissue and the soft tissue around the wall of cyst. Based on clinical history, imaging studies, pathological findings and absence of extramediastinal tumor, a diagnosis of thymic adenocarcinoma associated with thymic cyst was established. The patient was alive without any sign of recurrence 7 months after the operation.
Keywords: Thymic cyst; pathology; thymic carcinoma.