Nonossifying Fibroma in the Mandible of a Goat

An 8-year-old male Nubian goat was presented with a peracute history of straining to urinate and unilateral mandibular swelling. At necropsy, the rostral half body of the left mandible was distorted by fusiform swelling that, on sagittal section, had marked medullary bone loss and replacement with a well-demarcated fibrous mass. Histologically, the mass comprised streaming spindloid cells with whorls and storiform patterns, interspersed with numerous multinucleated giant cells. Bone formation was not present in the neoplasm. The mandibular mass was diagnosed as nonossifying fibroma, a relatively common tumor in children but seldom reported in domestic animals.