Avitene granulomas of colonic serosa.

Avitene, microfibrillar collagen hemostat, is an absorbable topical hemostatic agent prepared from purified bovine corium collagen. A case is reported of a 58-year-old man who, one month after sigmoid colectomy for volvulus in which Avitene as used to control bleeding from a splenic capsular tear, developed symptoms of intestinal obstruction. On exploratory laparotomy, the transverse and descending colon had numerous 0.1 to 2.0 cm nodules, adherent to the serosa of the bowel and mesentery, with kinking and partial obstruction of the splenic flexure. Light microscopically, the nodules were found to be composed of chronic inflammatory and granulomatous reaction with numerous deposits of eosinophilic fibrillar material consistent with Avitene. Electron microscopic examination of the lesions and of Avitene confirmed the nature of this material. The practical and pathobiological implications of utilization of Avitene as a hemostatic agent are discussed.