[A Case of Giant GIST Originating from the Greater Omentum].

A 60-year-old woman was admitted for abdominal distention, abdominal pain, and anorexia. Abdominal CT showed a 30×20 cm mass with contrast effect. gastrointestinal stromal tumor(GIST) of the omentum or the mesenterium was suspected. Peritoneal nodules were also recognized. We performed palliative surgery. The tumor was considered to have originatedfrom the greater omentum andinvolvedthe marginal artery of the transverse colon. We performedpartial excision of the transverse colon andresection of the tumor. Immunohistochemically, the tumor cells were c-kit(+), CD34(+), S100(-), andDOG1(-), with 1 fission image for 50 fields of view with high magnification. The patient was diagnosed with high-risk GIST originating from the greater omentum. The patient was started on imatinib administration on the 37th day but died on the 109th day.

[A Case of Liver Metastasis from a Primary Adenocarcinoma of the Appendix Presenting Five Months after the Initial Surgery].

A 70-year-old man with lower right quadrant abdominal discomfort was admitted to our hospital. Colonoscopy identified a villous tumor protruding into the cecal lumen from the appendiceal orifice. Abdominal computed tomography(CT)revealed a cecal tumor with a swollen appendix. An appendiceal cecal tumor with obliterative appendicitis was diagnosed, and we performed an appendicectomy with removal of part of the cecum. On pathological examination, well to moderately differentiated adenocarcinoma with infiltration of the proper muscular layer was diagnosed. No additional treatment was given as the patient refused further surgery and chemotherapy. However, a metastatic tumor in S4/8 of the liver was seen on CT 5 months after the initial surgery. A resection of liver metastasis was performed after chemotherapy. We report herein a rare case of primary appendiceal adenocarcinoma reoccurring shortly after surgery.

[Synchronous Double Cancer Involving Gastric Cancer Resembling a Submucosal Tumor with Stenosis in the Pylorus and Ascending Colon Cancer - A Case Report].

An 82-year-old woman presented to our hospital with a complaint of frequent vomiting. She was admitted for intensive examination and treatment. Abdominal computed tomography revealed that her stomach was severely expanded, and the wall of the ascending colon was thickened throughout its circumference. Upper gastrointestinal endoscopy uncovered severe stenosis in the pylorus and an elevated lesion resembling a submucosal tumor on the posterior wall of the pylorus. Biopsies of the lesion revealed that it was of Group 1. On colonoscopy, type 2 cancer was found in the ascending colon throughout the circumference, and the biopsies revealed that it was of Group 5. Upper gastrointestinal endoscopy was repeated, and the same result was obtained. The possibility of malignancy could not be excluded; therefore, distal gastrectomy and right colectomy were performed. In terms of histopathology, both resected specimens displayed poorly differentiated adenocarcinoma; however, immunohistochemical studies revealed differences in staining at the two sites. The case was diagnosed as synchronous double cancer involving gastric cancer resembling a submucosal tumor with stenosis in the pylorus and ascending colon cancer. Gastric cancer resembling a submucosal tumor is usually difficult to diagnose on biopsy. If the endoscopic findings reveal an elevated lesion resembling a submucosal tumor with stenosis, then the possibility of carcinoma should be considered, and the most suitable treatment should be selected.