Neuroendocrine carcinoma arising in a mediastinal teratoma with pulmonary metastasis: a case report and the chemotherapy response.

Neuroendocrine carcinoma as a somatic-type malignancy (STM) arising in an extragonadal teratoma is extremely rare. The effect of chemotherapy has been poorly evaluated in such cases contrary to teratomas with other STMs. We herein demonstrate that systemic chemotherapy may be beneficial in a case of neuroendocrine carcinoma arising in a mediastinal teratoma with pulmonary metastasis. A 31-year-old man presented with mediastinal widening visualized on a chest radiograph. Computed tomography showed a huge mediastinal mass with two pulmonary nodules. Surgical resection confirmed the presence of a neuroendocrine carcinoma arising in a mediastinal teratoma and pulmonary metastasis. The patient subsequently received chemotherapy and has had no recurrence during the 28-month follow-up.