A 66-year-old man underwent laparoscopic total gastrectomy with D2 lymph node dissection for gastric cancer and partial resection of the small intestine for a gastrointestinal stromal tumor (GIST). The pathological diagnosis of the gastric cancer was pT1b, N0, M0, Stage IA, with venous invasion. The small intestinal GIST was considered to be a very low-risk tumor. At 1 year after surgery, multiple liver tumors were identified. These tumors were diagnosed as neuroendocrine carcinoma based on examination of biopsy specimens. A retrospective re-analysis of the resected gastric specimen showed 10% synaptophysin-positive cells around gastric cancer cells with poorly differentiated adenocarcinoma. Therefore, we hypothesized that neuroendocrine differentiation from poorly differentiated adenocarcinoma in gastric cancer cells had occurred. Accordingly, a diagnosis of metastatic neuroendocrine carcinoma of the liver was made. Conditions such as neuroendocrine differentiation in a small number of cancer cells in early gastric cancer and development of multiple liver metastases are very rare. The biological features and optimal treatment strategies for this condition are unclear. Therefore, accumulation of further cases is needed.

Retroperitoneal penetration of a duodenal diverticulum is life-threatening due to subsequent abscess formation and sepsis. We report a case of this disease that was successfully treated with combined surgical treatments, including use of a duodenum-decompression tube. An 80-year-old man visited our hospital with upper abdominal pain. Contrast-enhanced CT showed disruption of the wall of the inferior duodenal angulus and gas in the retroperitoneal space. Emergency laparotomy was performed under a diagnosis of duodenal penetration into the retroperitoneal space. We identified penetration of the diverticulum at the inferior duodenal angulus under duodenal mobilization. Because of the fragility of the diverticulum wall, we filled the hepatic round ligament into the space of the perforated diverticulum. To avoid dietary passage into the duodenal lumen, the duodenal bulb was dissected, followed by gastrojejunal anastomosis. A retrograde duodenal-decompression tube was placed from the afferent loop. The patient had no postoperative complications and was discharged on the 19th postoperative day. He is doing well and is in good health after removal of the duodenum-decompression tube in the third postoperative month.

Large bowel obstruction by a gallstone with a cholecystocolonic fistula is a rare condition, and the appropriate treatment strategy remains unclear. A 76-year-old female patient had asymptomatic cholelithiasis for more than 10 years. She visited our hospital because of abdominal pain and constipation for a week. Abdominal contrast-enhanced CT showed a fistula between the gallbladder and transverse colon, and a 6-cm gallstone impacted in the descending colon. The patient was diagnosed with descending colon obstruction by a gallstone through a cholecystocolonic fistula. Conservative treatment was deemed to be insufficient to release the bowel obstruction, and emergency surgery was performed. The patient underwent a one-stage procedure to release the bowel obstruction by partial resection of the descending colon and cholecystocolonic fistula dissection. She had no postoperative complications and was discharged home on the 17th postoperative day. We review the reported cases of large bowel obstruction by a gallstone with a cholecystocolonic fistula and discuss the treatment strategy.

The patient was an 82-year-old man who had undergone right thoracotomy and reconstruction of the gastric conduit via the posterior mediastinum for lower thoracic esophageal cancer at age 60 years and had experienced no recurrence. He was diagnosed with distal bile duct cancer after a thorough examination for obstructive jaundice. Preoperative findings including 1 mm-slice CT showed no invasion of the tumor in the right gastroepiploic artery (RGEA). Therefore, we performed pancreaticoduodenectomy with preservation of the RGEA and gastric conduit, and achieved R0 resection. Postoperatively, ischemia in the gastric conduit or delayed gastric emptying was not observed. Despite recent improvements in preoperative imaging, it remains challenging to evaluate preoperatively whether a tumor in the pancreatic head region has invaded the RGEA. However, the diagnostic accuracy of tumor invasion using CT has been reported to be higher in bile duct cancer than in pancreatic cancer, and we succeeded in diagnosis of the absence of tumor invasion of the RGEA using 1-mm slice CT.

A 59-year-old woman was diagnosed with solid-pseudopapillary neoplasm (SPN) based on histopathological findings after distal pancreatectomy for a large tumor in the pancreatic tail at the age of 39. Thereafter, recurrence occurred at ages 49 and 55, and tumor resection was performed each time. At age 58, the patient had another recurrence and was treated with chemotherapy. However, this was ineffective, and the patient underwent surgery for the fourth time the following year. At age 62, she had another recurrence and underwent a fifth surgery. At age 64, local recurrence and bone metastasis were detected, and the patient was treated with radiotherapy. After age 68, the patient was transferred to palliative care, and she died 30 years after the first operation, at the age of 69. We report this case as an extremely rare example of an SPN for which multiple surgeries, chemotherapy, radiotherapy and multidisciplinary treatment were performed for local recurrence and in which long-term follow-up was possible.

A 75-year-old man was taken by ambulance to the emergency department with a complaint of severe abdominal pain after dinner. An enhanced CT scan showed a fish bone in a small intestinal diverticulum with an enhanced thick wall in the left pelvis without free air. A diagnosis of fish-bone migration and submucosal atopic tissue or a tumor of Meckel’s diverticulum was made. Abdominal pain resolved spontaneously during the course, but in consideration of the risk of perforation and the possibility of a tumor in the wall, single-incisional laparoscopic partial resection of the ileum was performed. The diverticulum was diagnosed as Meckel’s diverticulum because it was located approximately 60 cm from the ileocecal valve on the anti-mesenteric side of the ileum containing a full layer of the small intestine. A fish bone was found stuck in the Meckel’s diverticulum without evidence of perforation, which led to diagnosis of fish-bone migration into Meckel’s diverticulum. Histopathologic analysis revealed a 17-mm white submucosal tumor consisting of bundled spindle-like cells without mitosis. Immunohistochemical analysis showed the tumor to be positive for CD117 and CD34, and negative for desmin and S100. These findings confirmed the diagnosis of gastrointestinal stromal tumor arising from Meckel’s diverticulum.

A 51-year-old man with bloody stools was referred to our hospital for treatment of a mesorectal tumor. Abdominal contrast-enhanced CT showed a 65-mm lobulated tumor with a diffuse contrast effect in the mesorectum and slight continuity with the posterior wall of the rectum. Endoscopic ultrasound needle biopsy was performed, but no diagnosis was made. The lesion was suspected to be a tumor of the mesorectum or rectum, and was resected under robotic assistance. Histologically, the mass was composed of spindle-shaped cells growing without a specific arrangement (patternless pattern), which were immunohistochemically positive for STAT6 and CD34. The final diagnosis was solitary fibrous tumor (SFT). At 8-month follow-up, there was no tumor recurrence. We describe this case as an example of robot-assisted resection of a mesorectal SFT.