Mesenteric panniculitis of the sigmoid colon. Report of two cases.

Mesenteric panniculitis is an extremely rare disease in which the normal fatty architecture of the mesentery is replaced by fibrosis, necrosis, and calcification. Grossly, the mesentery is massively thickened and rubbery, with irregular areas of reddish-brown to pale yellow foci resembling fat necrosis scattered throughout. Microscopically, inflammatory involvement of the fibroadipose tissue shows round cells, foam cells, and giant cells. Macrophages that have ingested fat, also called lipophages, are the hallmark of the diagnosis. One hundred twenty-two cases of mesenteric panniculitis have been described in the literature; only three of these involved the large-bowel mesentery. This paper presents a review of the literature and two new cases that involve exclusively the mesentery of the sigmoid colon.