A Japanese female patient underwent a living lung transplant at age 29 and has been on immunomodulatory drug therapy since then. At age 52, she presented with sudden hematochezia. Despite abdominal computed tomography scan, esophagogastroduodenoscopy, and colonoscopy, no definitive source of bleeding was identified. Considering the possibility of small bowel bleeding, video capsule endoscopy was performed, which revealed a suspected ulcerative lesion in the jejunum. Subsequent per-oral double-balloon endoscopy confirmed the presence of an ulcerative lesion in the jejunum. A potential pathological diagnosis of post-transplant lymphoproliferative disorder (PTLD) was considered based on endoscopic biopsy specimens from the jejunal lesion. However, before the pathologic biopsy results were available, the patient experienced small intestinal perforation, necessitating emergency partial resection. Pathologic examination revealed a dense proliferation of medium-to-large atypical lymphocytes with neutrophilic infiltration in the perforated area of the small intestinal wall. Immunostaining showed lymphoid cells positive for CD20 but negative for CD3. Epstein-Barr virus (EBV) -encoded RNA was detected by in situ hybridization, and Ki-67 staining demonstrated a higher percentage of positive cells. Consequently, an EBV-positive diffuse large B-cell lymphoma, developed as PTLD, was diagnosed. Complete remission was achieved with a reduced immunomodulatory drug dosage and rituximab therapy. She has been alive for 8 months postoperatively without recurrence. This case suggests that PTLD should be considered in assessing patients presenting with abdominal symptoms following organ transplantation.

An 84-year-old male patient who was diagnosed with melena was admitted to the hospital with ischemic colitis. During the preparatory procedure for colonoscopy, he reported severe abdominal pain and exhibited decreased blood pressure. Obstructive colitis was suspected, and a colonoscopy was performed. A large amount of hard stool was found in the sigmoid colon, with ulcers and erosions exposing the submucosal layer observed on the proximal side. The endoscope was able to pass through the ileocecal region, and the patient's symptoms subsequently improved. The decline in intestinal function following ischemic enteritis may have contributed to the passage obstruction. Although fecal obstructive enterocolitis is extremely rare, caution is warranted during colonoscopy preparation.

The patient was a 73-year-old man who had undergone surgery for gastric cancer in January 2020 and was subsequently attending an outpatient clinic. In May, he presented with right upper abdominal pain. A computed tomography (CT) scan revealed an intraparenchymal rupture of a pseudoaneurysm in a segmental branch of the hepatic artery, and a transcatheter arterial embolization was performed. A follow-up CT scan in August showed a tumor in the same area. Retrospectively, the pseudoaneurysm in the segmental branch of the hepatic artery, which had experienced intraparenchymal rupture, was identified as the feeding artery for the tumor. In October, a right hepatic lobectomy was performed. Pathological examination confirmed a diagnosis of poorly differentiated hepatocellular carcinoma (HCC). This case highlights a rare instance of HCC causing intraparenchymal rupture.