Gastric adenocarcinoma with features of endodermal sinus tumor.

Extragonadal germ cell tumors are rare. The most common sites for EGGCTs are in midline locations such as the mediastinum, retroperitoneum and pineal gland. These tumors rarely present in the stomach. We describe here a case where a middle aged man presented with typical symptoms of gastric cancer. After extensive workup, which included blood work, CT abdomen scan, upper endoscopy, and endoscopic ultrasound, the patient was diagnosed with gastric cancer. However, due to very high blood levels of alpha-fetoprotein, the specimen was sent for special histochemical staining, which demonstrated that the tumor had features of both adenocarcinoma and endodermal sinus tumor. This is a very aggressive tumor with a very poor prognosis.