Germ Cell Tumor Targeting Chemotherapy in Gastric Adenocarcinoma with an Endodermal Sinus Tumor Component: A Case Report

The most common sites for extragonadal germ cell tumors are the midline mediastinum, retroperitoneum and, much less frequently, the stomach. The stomach-originated primary germ cell tumor carries a poor prognosis, especially when metastasis occurs to the liver, with a mean survival time of 1 month. We describe the case of a 77-year-old male who presented with usual symptoms of gastric malignancy. Gastrectomy was performed. Histopathology of surgically resected tissue revealed a mixture of adenocarcinoma and endodermal sinus tumor components with α-fetoprotein production. After liver metastasis was identified, oxaliplatin and capecitabine were administered as palliative chemotherapy. The response was poor. For the second-line therapy, bleomycin, etoposide, and cisplatin (BEP) therapy was initiated. The overall response to these drugs was a partial response and the residual liver lesion was considered to be resectable. The patient died of pneumonia 11 months following the BEP session, representing an overall survival time of 22 months. Gastric adenocarcinoma with a germ cell tumor component is uncommon and an effective combination of chemotherapeutic agents is not yet clear. In this case, the patient received germ cell tumor-targeting chemotherapy and showed a durable response. Hence, germ cell-targeting cytotoxic agents have potential as the 'front-line regimen'.