Primary gastric chorioadenocarcinoma: a needle in a haystack

Abstract

Primary gastric chorioadenocarcinoma (PGC) is an exceedingly rare neoplasm which is often misdiagnosed as gastric adenocarcinoma at presentation. A markedly elevated serum beta human chorionic gonadotrophin (Beta HCG) level is a characteristic feature of this tumor. A 44 year old white male presented with generalized abdominal pain and fullness, tarry black stools and weight loss of 3 months duration. Medical work-up including imaging with CT scans revealed the presence of a gastric mass and multiple liver metastases. Tumor markers were significant for a Beta human chorionic gonadotrophin (Beta HCG) of 23717.5 MIU/ML. Scrotal ultrasound did not show the presence of a testicular mass. Upper GI endoscopy with biopsy was positive for a poorly differentiated adenocarcinoma with Beta HCG staining on immunohistochemistry. The patient was diagnosed with metastatic PGC. He received four cycles of chemotherapy with Bleomycin, Etoposide and Cisplatinum. At the end of the fourth cycle, Beta HCG was 23 MIU/ML. CT scan for restaging, however showed an increase in the size of the metastatic lesions. The patient subsequently became profoundly pancytopenic, developed disseminated intravascular coagulation (DIC) and expired 12 months after initial presentation. PGC genetically and morphologically represents an adenocarcinoma and a choriocarcinoma. The significance of an elevated serum Beta HCG is controversial and it may have a role in evaluating response to treatment and tumor recurrence. Curative resection, appropriate chemotherapy and the absence of metastatic lesions is associated with improved survival. Hence, a high index of suspicion must be maintained to diagnose this tumor correctly at presentation and tailor therapy accordingly.