De novo thymic carcinoma or malignant transformation: a myasthenic patient presented with multiple mediastinal tumours.

A 63-year-old man presented with bilateral ptosis, and detailed evaluation confirmed ocular myasthenia gravis with three anterior mediastinal masses on computed tomography (CT) of the chest. Extended thymectomy was performed, and pathology revealed two thymic carcinoma and one thymoma. After surgery, the patient is free from recurrence. Synchronous triple thymic carcinomas and thymoma have not been reported. The finding of this case report supports the hypothesis of malignant transformation of thymoma to thymic carcinoma. Thymic carcinoma should be considered in the differential diagnosis of multiple thymic tumours, and extended thymectomy should be the treatment of choice.