Delineation of the Proliferative Component of Inflammatory Fibroid Polyps of the Intestine

Formalin-fixed, paraffin-embedded tissues from eight intestinal inflammatory fibroid polyps were analyzed using immunohistochemistry and flow cytometry to determine their immunohistochemical properties, DNA content, and the nature of the proliferat ing cells. In all cases, stromal cells stained diffusely for vimentin and focally for actin and histiocytic markers. Cell proliferative activity was assessed by flow cytometry and proliferating cell nuclear antigen staining. The S phase fraction was significantly in creased in inflammatory fibroid polyp when compared to control normal bowel tissues (10.8% ± 8.6% vs 6.7% ± 1.6%, P < .02). S phase fraction and proliferating cell nuclear antigen correlated in the stromal cells (r = 0.78, P < .05). Our data indicate that inflammatory fibroid polyps represent reactive, benign lesions containing poly clonal cell populations with diploid DNA content, and they have increased proliferative activity compared with normal intestinal tissues. Both the stromal cells and the vascu lar cells contributed to the proliferative activity of the lesion. Int J Surg Pathol 2(3): 207-214, 1995