A 79-year-old male with a positive fecal occult blood test result underwent total colonoscopy, which revealed a 15-mm-semipedunculated polyp in the rectum. The polyp appeared to be an adenoma using narrow-band imaging observation in magnifying endoscopy, although a 3mm reddish segment with a different surface structure was identified adjacent to the base of the polyp. En-bloc endoscopic mucosal resection (EMR) was performed. From the pathological evaluation using the specimen, the polyp was mainly a tubular adenoma with an adenocarcinoma component within the lesion. Additionally, a tiny plasmablastic lymphoma (PBL) component, which was positive for CD45, CD79a, CD30, CD38, MUM1, and lambda light chain;negative for CD3, CD5, CD20, CD56, CD138, cyclin D1, PAX5, IgG, IgA, IgM, IgE, HHV8, and kappa light chain, coexisted near the stalk. The proliferation index using Ki-67 immunohistochemistry was approximately 80%. Furthermore, Epstein-Barr virus-encoded RNAs were identified in in-situ hybridization, although the human immunodeficiency virus was not detected. The patient received contrast-enhanced computed tomography (CT) and positron emission tomography-CT (PET-CT) follow-ups after treatment without recurrence for two years. This is the first report of gastrointestinal PBL that could be treated using EMR.

A Japanese male in his 50s was presented to our hospital with the chief complaint of positive fecal immunochemical test. He had a history of hypertension. He underwent colonoscopy and was diagnosed with sigmoid colon cancer. He also underwent laparoscopic sigmoid colectomy with D3 lymph node dissection for sigmoid colon cancer. The inferior mesenteric artery and inferior mesenteric vein were amputated at the root of the vessels. The patient received adjuvant chemotherapy and was recurrence-free. Eleven months after the surgery, lower abdominal pain during defecation appeared. Contrast-enhanced computed tomography (CT) and colonoscopy showed marked rectal mucosal edema and increased fatty tissue density (dirty fat sign) around the anorectal side of the anastomosis. Intestinal blood flow was maintained. There were many fine blood vessels around the rectal wall, and the amputated distal part of the superior rectal artery was retrogradely contrasted. Amputated superior rectal artery and superior rectal vein were dilated than before. Colonoscopy revealed mucosal redness, edema, and easy bleeding on the anorectal side of the anastomosis. Abdominal contrast-enhanced 3D-CT showed increased arterial blood flow and increased fine blood vessels around the rectal wall. It suggested the presence of an arteriovenous fistula and venous congestion. Conservative treatment with total parenteral nutrition and prednisolone infusion did not improve the patient's condition, and a colostomy was performed. After colostomy, the pain improved, and the CT scan of the abdomen showed improvement in arterial blood flow and venous congestion. Colostomy was closed after 10 months. There has been no relapse since the closure of the colostomy. There are few reports on ischemic proctitis on the anorectal side of the anastomosis after colon cancer resection due to impaired venous blood flow.

We present a case of 63-year-old male patient who underwent subtotal stomach-preserving pancreaticoduodenectomy for pancreatic neuroendocrine tumor (NET) G2. He had been followed up for three years and had no signs of recurrence postoperatively. Five years after surgery, he had abdominal pain. Upper gastrointestinal endoscopy showed a gastric tumor. Laparoscopic distal gastrectomy was performed without postoperative complications. The histopathological findings of the resected specimen were consistent with mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). The immunohistochemical characteristics of the gastric MiNEN lesion were different from those of the pancreatic NET lesion resected five years ago, suggesting that those lesions were heterochronous.

A woman in her 60s was referred to the Department of Gastroenterology with anemia. She had a recurrent transient loss of consciousness 11 years ago, and she was examinated at the cardiology and neurology departments, but the cause was not identified. Epileptic seizures were suspected. Sodium valproate medication was started, and the patient's condition progressed with no recurrence. Esophagogastroduodenoscopy showed a tiny submucosal tumor-like lesion with mild depression in a 21cm thoracic esophagus. Biopsy revealed epithelioid granulomas with multinucleated giant cells in the subepithelial stroma. Computed tomography (CT), positron emission tomography-computed tomography (PET-CT), and magnetic resonance imaging (MRI) showed multiple lesions in the hilar lymph nodes, spleen, and heart that are typical of sarcoidosis. These findings led to the diagnosis of esophageal lesion associated with sarcoidosis. The patient had no subjective symptoms;however, treatment with prednisolone 30mg was started because cardiac sarcoidosis is a risk of death. Gastrointestinal tract involvement in sarcoidosis is rare;esophageal sarcoidosis is particularly rare, and there are few reports on superficial lesions. Here, we report a case of sarcoidosis that was diagnosed from a tiny esophageal lesion.

A 57-year-old male patient with unresectable pancreatic head cancer was treated with chemotherapy, 5 courses of gemcitabine plus nab paclitaxel therapy, and 9 courses of gemcitabine monotherapy. After 12 months of treatment, he was admitted to our hospital with headache and dyspnea. He was diagnosed with gemcitabine-induced thrombotic microangiopathy (TMA) due to acute kidney dysfunction, hemolytic anemia, and thrombocytopenia. Gemcitabine was discontinued, and symptoms were improved without using hemodialysis and plasma exchange. After his renal function recovered, we started S-1 chemotherapy. Eighteen months later, the patient was alive. Looking back, we realized that fragment red blood cells appeared in complete blood count and serum LDH elevated at 5 months prior to admission, serum creatinine level increased slowly at 4 months prior to admission, and blood pressure elevated significantly at 2 months prior to admission. Therefore, physicians must be aware of TMA as a possible adverse event to gemcitabine. As in this case, hemolytic findings and hypertension in patients treated with gemcitabine may help early detection of TMA.

A 62-year-old male patient was referred to our hospital for jaundice and bloody feces. He had hyper-IgG4-emia. Computed tomography (CT) showed diffuse pancreatic enlargement, pancreatic pseudocyst, and hematoma of the splenic flexure of the colon. Magnetic resonance imaging (MRI) showed a fistula in the pancreatic pseudocyst and splenic flexure of the colon. Moreover, lower gastrointestinal endoscopy showed a fistula in the same region. Endoscopic retrograde cholangiopancreatography (ERCP) showed narrowing of the main pancreatic duct and stenosis of the lower bile duct. Following this, the patient was diagnosed with autoimmune pancreatitis-induced pancreatic pseudocyst and colonic perforation-induced gastrointestinal bleeding. The pancreatic pseudocyst and fistula were resolved through steroid treatment.