Sigmoid stricture in a 39-year-old female

Clinical presentation A 37‐year‐old woman with confirmed ulcerative colitis (proctosigmoiditis), receiving mesalamine as medical prophylaxis, was referred to our unit with a 6‐month history of recurrent colic abdominal pain that was more severe in the pelvic region. The pain was associated with constipation; the patient also complained of dysmenorrhoea and abnormal menstrual bleeding. Physical and rectal examinations were normal. During the previous 6 months, the patient had had a normal blood count, erythrocyte sedimentation rate (20 mm/h) and C‐reactive protein (<1.0 mg/l). Colonoscopy was performed only to the distal sigmoid colon because of a tight sigmoid stricture due to extrinsic compression; mucosal biopsies were normal. Abdominal ultrasound and contrast‐enhanced CT scanning were performed. Transabdominal ultrasound revealed an ovarian cystic mass with diffuse low‐level homogeneous echoes. This lesion invaded the serosal surface of the colon and caused a focal thickening of the sigmoid colon wall (arrows) (figure 1). The CT image showed a right adnexal mass with a thin ring within it (small arrow); this lesion adhered strongly to the rectosigmoid segment and compressed it (large arrows) (figure 2). Question What diagnosis is suggested by the radiological and clinical features? See page 1256 for answer This case is submitted by: