LAUSR

BACKGROUND Ischemic colitis with inferior mesenteric arteriovenous malformation (AVM) is a rare disease. Although a few reports have been published, no report has described the natural history of idiopathic mesenteric AVM. CASE SUMMARY A 50-year-old male was admitted to our hospital due to abdominal pain that had persisted for 3 mo and bloody diarrhea. He had no history of trauma or abdominal surgery. He had undergone two colonoscopies 6 mo and 2 years ago, and they showed only a polyp. He was diagnosed with ischemic colitis with inferior mesenteric AVM following contrast-enhanced abdominal computed tomography (CT) and underwent rectal low anterior resection. He has not had a recurrence of symptoms for 3 years. His history showed that he had undergone non-enhanced abdominal CT 2, 5, and 8 years ago when he had attacks of urinary stones. Retrospectively, dilation of blood vessels around the rectosigmoid colon could have been detected 5 years ago, and these findings gradually became more evident. CONCLUSION This is the first report of the natural history of inferior mesenteric AVM.