Cap polyposis mistaken for Crohn's disease: case report and review of literature.

We report the case of a 19-year old male who presented with collapse and hypoglycemia associated with two weeks of frequent hard stools, abdominal pain relieved by defecation, postprandial vomiting and significant weight loss. Radiologically and endoscopically a diagnosis of Crohn's colitis was made and the patient was treated with steroids and immunosuppression. Following several hospital admissions treatment had to be escalated to include anti-TNF-α agents. Despite maximum therapy the patient continued to deteriorate symptomatically and biochemically with severe hypoalbuminemia and persistent anemia and a total colectomy was performed. Intra-operative finding was that of an inflamed large intestine and pseudo-polyposis but histology was reported as cap polyposis. The specimen was compared with the biopsies obtained from the earlier colonoscopies and it was felt that the previous samples were taken from areas of severely inflamed polypoid mucosa with histology mimicking colitis in inflammatory bowel disease.