Papillary adenocarcinoma in a thymic cyst: a pitfall of thoracoscopic excision.

Carcinoma arising in a thymic cyst is very rare. We performed thoracoscopic subtotal resection of an assumed benign cyst. The patient had a reoperation when the diagnosis of papillary adenocarcinoma was established. Complete resection and pleural thermochemotherapy were performed. The patient died 26 months later from systemic metastases. Caution must be exercised when managing nontypical thymic cysts.