An ultrastructural study of a jejunal inflammatory fibroid polyp.

Ultrastructural appearances of a small intestinal inflammatory fibroid polyp are reported. There is a vascular scaffolding, with interstices which contain regular and fibrous long-spacing type collagen, condensed lamellar basement membrane fibroblasts, basophils, some eosinophils and histiocytes. In addition other cells less easily characterized but believed to be of an endothelial and primitive mesenchymal cell nature are recognized. Possible origins of the polyp are considered.