A 29-year-old woman diagnosed with ulcerative colitis two months earlier was admitted with 9?10 episodes of diarrhea per day accompanied by hematochezia. Despite intravenous corticosteroids and oral 5-ASA therapy, symptoms persisted, and infliximab and azathioprine were initiated. On day 5 after treatment escalation, she developed severe abdominal distension and pain. Abdominal radiography showed the findings in Fig. 2. What is the most appropriate treatment?

A 78-year-old man presented with persistent abnormal findings on abdominal CT performed three months after treatment for abdominal pain at another hospital. He had no abdominal pain, fever, nausea, or vomiting at presentation. Physical examination was unremarkable. Based on the CT findings, what is the most appropriate management?

A 54-year-old woman presented with epigastric discomfort. She had no significant past medical history and did not smoke or consume alcohol. Physical examination and laboratory tests were unremarkable. Upper gastrointestinal endoscopy revealed the findings shown in Fig. 1, and CLO test and biopsy findings are shown in Figs. 2 and 3. What is the most appropriate next diagnostic test or treatment?

A 61-year-old man with alcoholic liver cirrhosis was incidentally found to have the following lesion on endoscopy (A). Abdominal CT demonstrated a shunt between the lesion and the renal vein (B, red circle). As the patient was residing in the Philippines with limited access to medical care, prophylactic treatment was performed prior to departure (C). What treatment did the patient receive?

A 66-year-old man presented with melena that began on the day of admission. His vital signs were stable, and the hemoglobin level was 7.8 g/dL. Upper and lower gastrointestinal endoscopy failed to identify the source of bleeding. Abdominal computed tomography (CT) (A) and double-balloon enteroscopy (B) revealed a tumor in the small intestine, and surgical resection was performed. Based on the histopathologic findings (C), what is the most likely diagnosis?