Clinical presentation

A 27-year-old woman presented with 1 week of bright red rectal bleeding with generalised abdominal pain and loose stools. She had experienced three similar episodes that settled spontaneously in the year prior. Relevant past history included subcutaneous masses on left shoulder, left elbow and right paravertebral region since childhood and migraine. There was no history of inflammatory bowel disease or previous infective colitis. On clinical examination, she was haemodynamically stable. There was a cutaneous vascular lesion present on her left lower limb that was thought to represent a port-wine naevus (capillary malformation). Abdominal examination revealed generalised tenderness with no guarding, rigidity or palpable masses. Rectal examination revealed external haemorrhoids. Basic blood parameters were all within normal limits. Stool sample revealed …