We report on a case of Stage IV gastric cancer in which a primary lesion showed a complete response and a target lymph node showed partial response (PR) 10 months after the administration of nivolumab. An 80-year-old woman complained of anorexia. Esophagogastrodoudenoscopy revealed type 3 gastric cancer. Biopsy specimens were classified as Group 5, poorly-differentiated adenocarcinoma. CT examination showed an enlarged #11 lymph node (LN) and swelling of #16a2 LN. PET/CT showed accumulation in the primary lesion and #2 LN. We diagnosed it as cT4aN3cM1(LYM) cStage IV. Though we performed chemotherapy with S-1 plus oxaliplatin as the 1st-line therapy, the adverse events and disease progression lead us to 2nd-line therapy with ramcirumab plus paclitaxel. As it also showed progressive disease (PD), we administered nivolumab as the 3rd-line therapy. Though the primary lesion shrunk, biopsy was Group 1, #11 LN enlarged slightly after 6 courses. It was very hard to judge whether we should continue administration of nivolumab or not, but we decided to continue, as her clinical symptoms and QOL were remarkably improved. We diagnosed PR after 19 courses as #11 LN shrunk markedly. Primary lesion showed scar formation, biopsy was classified as Group 1 again, and #11 LN shrank furthermore after 30 courses. She had been given nivolumab at that time. We believe this was a delayed response to nivolumab. Our findings suggest that there are cases of gastric cancer with delayed onset of tumor reduction effect through the administration of nivolumab.

Somatostatin receptor scintigraphy (SRS) is used to diagnose neuroendocrine tumors, but its clinical use in Japan remains limited. We encountered a case of pancreatic metastasis of renal cancer showing accumulation on the SRS. A 79-year-old woman underwent a left nephrectomy for cancer of the left kidney. A simple CT follow-up conducted 19 years after the operation revealed a mass-like lesion in the pancreatic body, and previous CT images were reviewed. This review showed that the dynamic CT conducted 12 years after the operation, had revealed a mass-like lesion in the pancreatic body that was heavily stained in the arterial phase, which gradually increased over time. Close examination using SRS showed increased accumulation throughout the tumor. A pancreatic neuroendocrine tumor was first suspected, and a distal pancreatectomy was performed. Histologically, the tumor contained a clear vesicle, which was diagnosed as pancreatic metastasis of renal cancer (clear cell carcinoma). SRS could indicate the accumulation in tumors other than neuroendocrine tumors; hence, caution must be exercised during the differential diagnosis of tumors with SRS.

A 25-year-old woman with a pancreatic cystic lesion was admitted to our hospital. She also had a history of repeated acute pancreatitis and melena. Contrast-enhanced abdominal CT revealed a multilocular cystic lesion in the pancreatic tail and a splenic artery aneurysm beside the cyst. The cyst included high-density content indicative of obsolete hematoma. Based on these findings, we diagnosed mucinous cystic neoplasm with hemosuccus pancreaticus caused by ruptured pseudoaneurysm into the cyst. We performed distal pancreatectomy after splenic artery embolization. Pathological findings showed mucinous cystadenocarcinoma with minimal invasion and ruptured aneurysm into the cystic tumor. Mucinous cystadenocarcinoma with pancreatitis or splenic artery pseudoaneurysm is rare, and we report this case with a review of the literature.

A 45-year-old man who presented with fever, polyarthritis and deafness was referred to our hospital, and given a diagnosis of granulomatosis with polyangiitis. Twelve days after starting corticosteroid and cyclophosphamide therapy, he suddenly developed abdominal pain. Abdominal CT scan showed an edematous small intestine with free air and fluid collection in the pelvis. Emergency laparotomy was performed for diagnosis of gastrointestinal perforation, which revealed 5–10 mm erythematous lesions at 20 sites on the anti-mesenteric side of the small intestine. Three of these lesions were perforated. Local resection with anastomosis were performed at each site. The postoperative course was uneventful, and medical treatment was resumed 9 days after the operation. Fifty-three days postoperatively, he developed abdominal pain again. Abdominal CT scan showed a partially-dilated small intestine with a small amount of ascites, suggesting a strangulated obstruction. Emergency laparotomy was performed, which showed edema at one of the previous anastomotic sites with a small amount of purulent ascites. There was no evidence of strangulation or perforation of the intestine. An omental patch was placed over the anastomotic site, and a drain placed in the pelvis. The postoperative course was uneventful, and he restarted medical treatment. Histopathology of the resected specimen showed vasculitis at the sites of perforation, suggesting a relationship with granulomatosis with polyangiitis. We report a patient with granulomatosis with polyangiitis with multiple perforations of the small intestine. Special attention should be paid for re-perforation in the treatment of the disease. Furthermore, medical information should be shared with patients and their families as well as medical staff.

A 23-year-old pregnant woman with a history of toxic multinodular goiter, multiple mammary and tonsillar tumors, and a family history of Cowden disease presented with abdominal pain and vomiting. Abdominal US and MRI revealed intussusception with small intestinal obstruction. We performed emergency surgery under the diagnosis of intestinal intussusception. Intraoperatively, we identified ileo-ileal intussusception (20 cm in length), which was reduced using the Hutchinson’s maneuver. A 2-cm sized mass was detected in the proximal part; therefore, the intussuscepted portion of the ileum was resected. Gross examination of the resected specimen showed multiple yellow polyps, and the lesion was diagnosed as a lipoma based on histopathological findings. Based on the detection of a lipoma and her history of goiter, in addition to a family history of Cowden disease, this patient was definitively given a diagnosis of Cowden disease.

A 73-year-old woman underwent subtotal colectomy with D2 lymph node dissection for invagination due to ascending colon cancer and perforative peritonitis 7 years previously. The patient underwent 2 surgeries for dissemination; the first was 3 years previously, followed by a second surgery 1 year previously. At this time, she complained of abdominal pain. Abdominal CT showed obstruction in the small intestine with enhanced tumor. Dissemination of ascending colon cancer was suspected and partial resection of the ileum was performed. On the resected specimen, type 1 tumor was identified, which did not invade the serosal membrane side. Pathological findings revealed that papillary adenocarcinoma continued to the small intestine epithelium, and the tumor was diagnosed as primary small intestinal cancer. Her postoperative course was uneventful, and she was discharged on postoperative day 31. Presently, she is alive after 14 months without tumor recurrence or metastasis. Patients that present with small intestinal cancer after colorectal cancer are very rare. However, the number of patients with cancer of other organs after colorectal cancer has been increasing. It is important to pay attention not only to recurrence, but also to cancer of other organs including the small intestine.

An 80-year-old woman presented with several days’ history of right lower abdominal pain. Her CT scan showed thickening of the wall of the appendix and the ileocecum. Biopsy confirmed the diagnosis of a poorly differentiated adenocarcinoma of the appendix, and ileocecal resection was performed. Macroscopically, the tumor was observed to arise from the appendix. Histopathological analysis revealed the invasion of large atypical cells which were positive for synaptophysin and chromogranin A by immunohistochemical staining. Since the Ki-67 index was 70%, the lesion was diagnosed as a primary neuroendocrine carcinoma of the appendix. Although the postoperative course was uneventful, she developed liver metastasis and pleural dissemination only 2 months after the operation. Moreover, her general condition gradually got worse and she died 5 months postoperatively. Neuroendocrine carcinomas have an aggressive clinical course and are associated with poor prognosis. Here, we report a rare case of primary neuroendocrine carcinoma of the appendix.

An 86-year-old woman was originally given a diagnosis of left-sided colitis-type ulcerative colitis (UC) in 2008 and received treatment at another hospital. In February 2018, high fever and bloody stool were noted, and she was referred to our hospital because of UC exacerbation. The patient was found to be affected by a reduced level of consciousness and anemia progression, and total colectomy and ileostomy procedures were performed for acute exacerbation of UC. Following surgery, the level of consciousness did not improve and meningeal symptoms were observed, thus a cerebrospinal fluid examination was performed. Cerebrospinal fluid test findings showed elevated protein and cell counts, and a cerebrospinal fluid glucose/blood glucose ratio lower than 0.4, which led to a diagnosis of bacterial meningitis. Furthermore, preoperative blood culture findings revealed Listeria monocytogenes, thus the case was considered to be Listeria meningitis. The condition of the patient improved with antibiotic administration of ampicillin and gentamicin. This was an active UC case, in which bacterial invasion from the digestive tract was considered to have occurred.

[Case 1] An 82-year-old man presented with a 3-month history of defecation difficulty. Preoperative examination revealed prostatic cancer and rectal cancer. The patient subsequently underwent a Hartmann’s operation with D2 lymph node dissection in July 2011. A histopathological examination revealed a “collision” metastatic rectal (cytokeratin-7 negative, cytokeratin-20 positive) and prostatic (cytokeratin-7 and cytokeratin-20 negative, prostate-specific antigen positive) carcinoma in the pararectal lymph node. [Case 2] A 64-year-old man presented with a 2-month history of urinary disorder and constipation. Preoperative examination revealed prostatic cancer and sigmoid colonic cancer with multiple liver metastases. The patient subsequently underwent a Hartmann’s operation with D3 lymph node dissection in July 2017. A histopathological examination revealed a metastatic prostatic (cytokeratin-7 and cytokeratin-20 negative, prostate-specific antigen positive) carcinoma in the lymph node of the mesocolon. We encountered rare cases of metastatic prostatic cancer to mesenteric lymph nodes, with the “collision phenomenon” in one lymph node.

A 39-year-old woman was referred to our department because of a pancreatic head tumor, diffuse cystic lesions in the pancreas, and a right renal tumor detected in a medical check-up. The pancreatic head tumor was diagnosed as pancreatic neuroendocrine tumor (PanNET) G1 by endoscopic ultrasound-guided fine-needle aspiration, and the renal tumor was clinically diagnosed as renal cell carcinoma (RCC). The patient was suspected of suffering from von Hippel-Lindau (VHL) disease. Genetic testing found mutation in exon 2 of VHL gene which resulted in definitive diagnosis of VHL disease. Pancreaticoduodenectomy and right partial nephrectomy were performed in one stage. Histopathological examinations revealed PanNET G1 with regional lymph node metastasis, serous cystadenoma (SCA), and clear cell renal cell carcinoma. Here, we describe a rare case of a VHL patient with PanNET, SCA and RCC.