Primary gastric choriocarcinoma: two case reports and review of the literatures.

Primary gastric choriocarcinoma (PGC) is a rare tumor, and its pathogenesis is still uncertain. Most PGCs have been reported to possess an adenocarcinoma component of variable extent, and pure PGC is especially rare. The diagnosis of PGC is confirmed by exhibition of choriocarcinomatous components on biopsy and exhibition of beta-hCG positive cell on immunohistochemical stain and elevation of the serum beta-hCG. Moreover it must be confirmed that no other site including gonads displays any tumor masses. The PGC tends to be more invasive and to have early metastasis. The median survival is known to be less than several months. We report two cases. The first case was a 62 year-old man who was diagnosed as advanced gastric cancer (AGC) by endoscopic biopsy with hepatic metastasis and received palliative chemotherapy with modified FOLFOX regimen and Genexol plus cisplatin regimen. He underwent subtotal gastrectomy due to perforation of the stomach during chemotherapy. On post-operative biopsy, He was re-diagnosed as PGC and received another palliative chemotherapy modified FOLFIRI, BEP, EMACO, VIP. However, multiple liver metastases were aggravated, and also serum AFP level increased. Ultimately, the patient died 10 months after initial diagnosis. Another case was a 45 year-old man. On endoscopic biopsy, he was diagnosed as AGC of adenocarcinoma. On Chest and Abdomen CT, multiple pulmonary and hepatic metastasis were also confirmed. On liver biopsy, He was diagnosed as PGC. The immunohistochemical stains were performed and the results were cytokeratin positive, EMA negative and beta-hCG weak positive. The serum beta-hCG level was highly elevated. BEP, VIP and EMA/CO combination therapy were administered, but he died at 12th months after the initial diagnosis.