[A case report of gastric cancer consisting predominantly of undifferentiated carcinoma].

We encountered a rare case of gastric cancer consisting predominantly of undifferentiated carcinoma.The patient was a 64-year-old man who underwent various tests because of symptoms of dysphagia in September 2012.We found a subcircumferential type II tumor at the gastroesophageal junction.A total gastrectomy, splenectomy, and Rouxen-Y reconstruction were performed.Adhesiotomy was also performed for the ileus on postoperative day (POD)2.The patient subsequently experienced septic shock with disseminated intravascular coagulation (DIC) and acute kidney failure due to complications of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia and MRSA colitis.As a consequence, the patient required respiratory management and continuous hemodiafiltration (CHDF). In addition, the patient experienced hemorrhage from the Roux-en-Y-anastomotic site in the contact with the ileus tube during treatment for septicemia on POD14, which was resolved with endoscopic treatment.Moreover, a cholecystectomy was performed on POD52 for gangrenous cholecystitis.The patient's progress was satisfactory.The pathology results revealed an undifferentiated carcinoma with the following characteristics: pT4a (SE), ly1, v0, pPM1, pDM0, type 2, 80 × 75 mm, UE, Less.In addition, immunostaining results revealed a tumor consisting of at least 90% of undifferentiated carcinoma tissue.Four months after surgery, local recurrence at the site of the esophagojejunostomy, disseminated recurrence around the left kidney, and metastases in the left adrenal gland appeared. The partial response (PR) was maintained by treatment with CPT-11+ cisplatin (CDDP) + trastuzumab.However, left adrenalectomy was performed 1 year and 4 months after the initial surgery was performed for metastasis to the left adrenal gland that started 10 months after surgery.One year and 10 months after the initial surgery, the patient continues to receive treatment with trastuzumab and has not exhibited signs of recurrence.