Germ cell tumors (GCTs) often occur in male testes and female ovaries. Extragonadal GCTs account for approximately 2% to 5% of all GCTs and mainly occur in the mediastinum, retroperitoneum, and pineal gland. In this study, we reported a rare case of gastric adenocarcinoma with GCT components. The patient's serum α-fetoprotein (AFP) level was higher than normal. Abdominal computed tomography (CT) showed a 10-cm × 10-cm tumor between the spleen and the bottom of the stomach. Gastric endoscopy indicated an ulcerative lesion extending from the bottom of the stomach to the antrum. Tissue biopsy identified the tumor as an adenocarcinoma. The patient underwent abdominal tumor resection, subtotal gastrectomy, D2 lymphadenectomy, and splenectomy. Postoperative histopathology showed that the tumor was a moderately to poorly differentiated adenocarcinoma. Immunohistochemistry analysis revealed positive staining for AFP, glypican-3, and placental alkaline phosphatase. Gastric adenocarcinoma with GCT components is particularly uncommon and rarely reported. Elevated serum AFP and/or β-human chorionic gonadotropin levels, abdominal CT, histopathology, and immunohistochemistry may help diagnose GCTs. Radical surgery resection is the primary treatment method for GCTs. Adjuvant chemotherapy and radiotherapy are effective for advanced GCTs.
Keywords: Germ cell tumor; case report; extragonadal germ cell tumor; gastric adenocarcinoma; radical surgery; α-fetoprotein.