Precardiac mass and femur fracture caused by multiple myeloma in a ferret (Mustela putorius furo).

A 5-year-old female spayed ferret was presented with lameness of the left hind limb and dyspnea. Five months earlier, the animal had been diagnosed with dilated cardiomyopathy and an undifferentiated precardiac mass. Clinical, radiological, and laboratory examinations revealed a left femoral neck fracture, mild anemia, and hyperglobulinemia. Due to the poor general condition and unfavorable prognosis, the animal was euthanized. Pathological examination identified the precardiac mass as multiple myeloma with dissemination to the mediastinum, spleen, liver, kidneys, adrenal glands, lymph nodes, and bone marrow. The neoplastic plasma cells were immunohistochemically CD138-positive and CD3-/CD79a-negative. This case demonstrates that plasma cell neoplasms in ferrets can also present as precardiac masses and should therefore be considered in the differential diagnosis.