Thymic carcinoma in myasthenia gravis developing years after thymectomy.

We report two patients with myasthenia gravis (MG) who underwent thymectomy but developed thymic carcinoma years after the initial surgery. In one patient, the initial thymic pathology was normal, whereas the other had an encapsulated benign thymoma that was found only on pathological assessment. These cases demonstrate that MG may occur as part of a "new" paraneoplastic syndrome even after thymectomy. The late appearance of metastatic thymoma raises questions about monitoring for these patients.