Germ cell tumor of the colon with an adenocarcinomatous component

A case of combined germ cell tumor and adenocarcinoma that arose in the colon of a 62-year-old man is described. The clinical and pathological findings are presented. The patient had widespread metastases at diagnosis and poor prognosis after operation (right hemicolectomy) was performed in spite of receiving chemotherapy. Pathologically, the germ cell tumor was composed of a yolk sac tumor and choriocarcinoma. Further, all the metastatic lesions showed a germ cell phenotype. An extragonadal germ cell tumor is extremely rare. To our knowledge, only a few cases have been reported in the English-language literature. Our present report will contribute to the understanding of the characteristics of this rare neoplasm.