Two cases of atypical carcinoid of the thymus.

We describe two cases of atypical carcinoid of the thymus. One was an 82-year-old woman with complaints of nonproductive cough and back pain, and the other a 64-year-old woman with no symptoms. Computed tomography scans of the chest in both cases revealed a large mass in the anterior mediastinum. Multiple metastases to bone and liver were also noted in the former case. Histological examination of their tumors revealed that the tumor cells were arranged in a nested, trabecular, or pseudorosette pattern, with increased numbers of mitoses, nuclear pleomorphism, and presence of necrosis. In addition, immunohistochemically, the cells stained for neuron-specific enolase, synaptophysin and chromogranin A. Combination chemotherapy consisting of carboplatin and etoposide was performed as initial chemotherapy in the former case and as adjuvant therapy in the latter. The former patient achieved a short-term partial response. It is important to differentiate atypical carcinoid from other thymic tumors, since such tumors including thymoma have a much better prognosis than does atypical carcinoid.