A Case of AFP-Producing, True Gastric Carcinosarcoma

The patient was a 79-year-old man with epigastralgia and vomiting. Endoscopic examination revealed a pedunculated tumor in his fornix. An endoscopically obtained tumor biopsy revealed an α-fetoprotein (AFP)-producing gastric carcinosarcoma. Computerized abdominal tomography detected the tumor and swollen lymph nodes, but no distant metastases. Serum AFP was 263.0 ng/ml. The patient was diagnosed as an AFP-producing gastric carcinoma, U, post, type I, cT3N1M0, cStage IIB, and underwent total gastrectomy with Roux-en-Y esophagojejunostomy and lymphadenectomy. The tumor specimen was 135 mm × 65 mm × 145 mm. Histopathologically, the tumor consisted of an epithelial component with a ductal conformation and a mesenchymal component with spindle-like cells. The epithelial component was positive on immunohistochemistry for keratin AE 1/3, CAM 5.3, and AFP. The mesenchymal component was positive for mesenchymal markers (desmin, CD56, and myogenin). There was muscular differentiation and the tumor appeared to be a true carcinosarcoma, U, Post, type 1, pT3(SS), ly2, v1, pN3a, pStage IIIB. The patient was discharged on the fourteenth postoperative day. Three months after operation, liver metastases were noted and he died three months later. Carcinosarcomas are categorized as true carcinosarcomas or so-called carcinosarcomas. There is no effective treatment for gastric carcinosarcoma except resection and its prognosis is very poor, with an average postoperative survival of 11 months. In Japan, 16 cases of true gastric carcinosarcoma have been reported, including this case. AFP-producing carcinosarcoma has been reported only once apart from our case. As gastric carcinosarcomas are rare and have a very poor prognosis, appropriate treatment must be identified.