Gingival Mucoperiosteal Fibroma-Clinical, Imaging, and Histological Review of a Novel Oral Fibroma in 27 Dogs

This case series describes the clinical, imaging, and histological features of 27 lesions diagnosed as a benign fibrous mass not previously described in veterinary literature. The authors propose the name gingival mucoperiosteal fibroma (GMPF) to describe these fibrous lesions found in dogs. Histologically, GMPF is characterized by a lack of odontogenic tissue and various degrees of ossification. GMPFs affect adult dogs with an average age of 95 months (range 24-156 months) and appear as expansile growths with superficial appearance matching the surrounding gingiva. The mandibular incisive region is the most commonly affected region (n = 13) and most cases have some level of bone proliferation radiographically (n = 14). Histological examination of the masses shows poorly cellular fibrous tissue with thick interwoven collagen fibers. Bony invasion by the mass was not noted, though histological proliferation of bone was seen in 17 lesions. Surgical resection was curative in all cases when performed, and no recurrence was seen at time of follow-up. Fibrous lesions of the oral cavity in dogs are poorly defined and categorized, though numerous lesions have been described in both human and veterinary literature.