Multiple Myeloma with Skin and Renal Involvement and Anaplasma Phagocytophilum Co-Infection in a Dog

An 11-year-old male Cocker Spaniel was presented with acute onset of apathy, polyuria and polydipsia. Blood examination showed hypoalbuminemia and hyperglobulinemia, while electrophoresis revealed monoclonal gammopathy. Subsequent tests showed glycosuria, proteinuria, a positive serology test for Anaplasma spp. and ultrasonographical changes of the liver and spleen. Urine electrophoresis confirmed the presence of Bence-Jones protein. The dog's condition deteriorated, and the dog had developed skin lesions on the neck and body. The owner decided to euthanize the dog and agreed to bone marrow and skin biopsy. Bone marrow cytology revealed an increased number of plasma cells and several cellular atypia. Histopathology of the skin lesions showed a round cell tumor of lymphoid or plasmacytoid origin. Subsequent immunohistology supported the diagnosis of multiple myeloma cutaneous involvement. This case report describes unusual features observed in a dog with multiple myeloma.