A caecal diaphragm in cystic fibrosis.

A right iliac fossa mass may be a difficult diagnostic problem in a patient with cystic fibrosis. We present a patient with such a mass who was thought to have a non-obstructing intussusception on clinical and radiological grounds. However, at laparotomy she was found to have a pathology not previously described in cystic fibrosis. She had a partial diaphragm almost blocking the lumen to her appendix. The differential diagnosis of a right iliac fossa mass is considered and the cause of her pathology discussed.