Mesenteric heterotopic ossificans in a ferret (Mustela putorius furo) : A rare cause of soft tissue ossification

Heterotopic ossification (HO) is a rare condition characterized by abnormal bone production in soft tissue. Very few cases of HO have been reported in animals (e.g., dogs and horses) and often this disease process is a consequence of a traumatic incident. A 5-year-old, male European ferret (Mustela putorious furo) was referred for anorexia, generalized weakness, and weight loss. Clinical examination revealed multiple abdominal masses. An explorative laparotomy identified omental, white/tan, nodular to coalescing hard lesions. The omentum and spleen were surgically removed during the surgical procedure, with both subsequently submitted for histopathologic evaluation. Microscopically, the omental masses were composed of a meshwork of lamellar and woven bone admixed with islands of cartilage and lacunae containing either blood, fat, and/or bone marrow. Multifocal mineralization and bone lamellae were also present in the grossly normal omentum. The finding of multiple bone nodules containing bone marrow and/or adipose tissue, with no Harversian system, and minimal intratrabecular connective tissue favored a diagnosis of HO.