Obstructing apple core lesion of the rectum: a case report of inflammatory pseudotumor masquerading as colorectal carcinoma.

Inflammatory pseudotumor is a rare lesion which can occur, typically in children and young adults, in many different organ systems. The tumor often clinically behaves like a cancer but without histological evidence of malignancy. This case study of a 14 year-old boy is the first report in the literature of an inflammatory pseudotumor presenting as an obstructing apple core lesion, mimicking a rectal carcinoma. A six-week course of non-steroidal, anti-inflammatory drugs (NSAIDs) led to complete resolution of the mass, and following resection of a residual stricture, the patient has been recurrence-free for seven years.