An intraperitoneal tumorous mass caused by granulomas of microfibrillar collagen hemostat (Avitene).

Microfibrillar collagen hemostat (Avitene) is an absorbable topical hemostatic agent prepared from purified bovine corium collagen. Herein, we report the case of a 56-year-old woman who had undergone an ovariohysterectomy for an ovarian mucinous cystadenocarcinoma 3 months previously and then required a second operation for an intraperitoneal mass associated with microfibrillar collagen hemostat. Microscopically, the resected mass was composed mostly of foreign-body granulomas with microfibrillar collagen hemostat materials. Microfibrillar collagen hemostat was used to control bleeding during the first operation. In a very small portion, however, a recurrent mucinous cystadenocarcinoma was also present. This case is worthy of note in that microfibrillar collagen hemostat may produce huge granulomatous masses that clinically mimic a neoplasm, inducing unnecessary and extensive treatment.