A 64-year-old woman received a third dose of SARS-CoV-2 mRNA vaccine. On the next day, she developed fever, diarrhea, and abdominal pain and had bloody stools. Total colonoscopy revealed deep ulceration on the whole colon. She was treated with corticosteroid and infliximab and her symptoms improved. She was diagnosed with severe enteritis resembling ulcerative colitis triggered by SARS-CoV-2 mRNA vaccination.

A woman in her 50s with a medical history of chronic hepatitis C virus (HCV) infection presented to our hospital with arthralgia, diarrhea, and fever. We performed colonoscopy and found scattered erosions at the terminal ileum. Furthermore, the biopsy specimen from the ileum and colon showed non-specific enterocolitis. Two weeks later, she was admitted to our hospital due to worsening neuropathy, proteinuria, and skin rash. On the next day, her abdominal pain worsened, and she had bloody stools. Repeat colonoscopy performed without bowel preparation revealed multiple erosions at the colon, and biopsy specimen from the colon exhibited narrowing of the lumen of the blood vessels. The presence of serum cryoglobulin and untreated chronic HCV infection is consistent with the diagnosis of hepatitis C virus-related mixed cryoglobulinemic vasculitis.

A 62-year-old male presented with right intercostal muscle pain. Clinical examination revealed muscular defense in the same area. Abdominal ultrasonography revealed a distended gallbladder and ascites effusion, but no gallstones or polyps were present. Contrast-enhanced computerized tomography was performed, which revealed luminal obstruction due to arterial dissection of the celiac artery and intrinsic hepatic artery. This finding suggested gangrenous cholecystitis; thus, urgent cholecystectomy was performed. Only a few cases of celiac artery dissection and only one case of gangrenous cholecystitis without stones have been reported. We report here an extremely rare case of celiac artery dissection.

A 70-year-old man presented to our hospital with fever and abdominal pain. A mass was found in the left lobe of his liver. Three months later, disseminated peritoneal nodules and ascites appeared. Liver biopsy and review laparoscopy did not lead to a diagnosis. Approximately five months later, a pathological autopsy was performed, and a final diagnosis of sarcomatoid intrahepatic cholangiocarcinoma was made. Differentiating sarcomatoid cholangiocarcinoma from sarcomatoid malignant peritoneal mesothelioma was difficult due to the similarity of clinical and pathological findings. Because the two diseases are treated differently, being able to differentiate them is a challenge in the future.

A man in his 70s was admitted to our hospital due to jaundice and upper abdominal pain. Laboratory findings indicated elevated serum hepatobiliary enzyme and amylase levels. Contrast-enhanced computed tomography revealed smooth wall thickening of the terminal bile duct (tBD) with a faintly enhanced inner line. ERCP revealed stenosis from the tBD to the ampulla of Vater (AV) with upstream dilatation. Intraductal ultrasound (IDUS) circumferentially revealed a thickened wall preserving a three-layered structure throughout the same region. Furthermore, a thick innermost hyperechoic layer was identified in the bile duct portion of the AV (Ab). Findings suggestive of adenocarcinoma were obtained from the tissue samples from the biliary stricture using biopsy forceps. Thus, pancreatoduodenectomy was performed. A pathological examination revealed a thickened AV wall spreading over the tBD with hyperplasia of the glands and smooth muscle fibers. In addition, low-grade biliary intraepithelial neoplasia (BilIN) was scattered throughout the lesion, and high-grade BilIN was partly observed in the peribiliary glands of the Ab. Based on these results, a diagnosis of carcinoma in situ arising in adenomyomatous hyperplasia (ADMH) of the AV was made. To date, there are no reports on ADMH-associated carcinoma of the BD or AV. We here report this original case with the IDUS findings, which are presumed to reflect the histologic features of ADMH showing ductal proliferation surrounded by smooth muscle fibers. Also, we discuss the process through which carcinoma arises from ADMH in AV.