Unusual cause of pelvis pain and polyuria in an adolescent: idiopathic megarectum.

A 16-year-old girl presented to the emergency department with subacute pelvic pain, painful micturition and polyuria for 3 days. She had a past history of dysmenorrhea and chronic constipation for many years without any relevant surgical history. Patient had no fever or vomiting. On examination the patient had a soft abdomen with non-tender pelvic mass. The abdominal plain film revealed a lower abdominal opacity (Fig. A) without any air-fluid levels or pneumoperitoneum. Abdominopelvic CT revealed fecal impaction in a megarectum (Fig. B) without significant colonic dilatation (Fig. C). Enemas failed to relieve the impaction. The surgical treatment was the only choice with resection of the rectum and coloanal anastomosis without any reported postoperative complications with improvement of the patient’s complains.