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.