Multiple myeloma in a German Shepherd Dog

A massive hypergammaglobulinemia was detected in a nine year old German She pherd Dog. Further examination revealed a thrombocytopenia, prolonged coagu lation times and splenomegaly. A biclonal IgA- and IgG gammopathy was demon strated in the serum and in the urine by means of serum- and SDS-PAG-electr ophoresis with subsequent Western- and immunoblotting. There were no radiog raphically detectable bone lesions at first presentations. A bone marrow ex amination showed an infiltration with more than 20 % plasma cells. Diagnosi s of multiple myeloma was based on the paraproteinemia and infiltration of the bone marrow with plasma cells. The dog was treated with Melphalan and P rednisolon and was in remission after 2 weeks of therapy. Seven months afte r initiation of the chemotherapy, the dog was presented with acute skeletal pain. MRI and myelography revealed an extradural compression at the level of the 13(th) thoracic vertebra. A laminectomy was performed and a neoplast ic process in this vertebra identified. The dog was euthanized. Necropsy re sults confirmed the diagnosis of multiple myeloma.