[Ileal inflammatory fibroid polyp: case report].

The inflammatory fibroid polyp is a rare, polypoid lesion in the gastrointestinal tract. It occurs in the stomach, small intestine, and large intestine in descending order of frequency. This case report shows an ileal inflammatory fibroid polyp that causes ileoileal intussusception. So far, the histogenesis and pathogenesis of these kinds of polyps are still uncertain. Under the microscopic examination, the lesion appears to be made up of spindle-shaped or stellate cells that are morphologically identical to proliferating fibroblasts. Immunostaining results are strongly positive for vimentin and focally positive for S100 protein. However, epithelial membrane antigen, factor VIII R Ag, smooth muscle actin, and lysozyme test are all negative. This favors the view that the inflammatory fibroid polyp is fibroblastic in origin.