Idiopathic sclerosing encapsulating peritonitis presenting as a right iliac fossa mass in a teenaged girl.

Sclerosing encapsulating peritonitis (SEP) is a rare peritoneal condition characterised by a firm and thick membrane that encases a part of or the whole of the small intestine. It can be idiopathic or secondary to a variety of conditions. It usually presents as an acute or subacute small bowel obstruction, however, the presentation can vary. It may be diagnosed by radiology, although definitive diagnosis is by laparoscopy or laparotomy. It is treated by excision of the covering membrane. We report a case of a teenaged girl who presented with abdominal pain and a palpable mass in the right iliac fossa. The patient underwent emergency laparotomy after her work up was inconclusive, and was found to have a case of SEP. The distal ileum and the sigmoid colon appeared to be covered by a thick membrane, which was excised. Follow-up of the patient was unremarkable. 2016 BMJ Publishing Group Ltd.