An unusual presentation of multiple myeloma in two cats.

Multiple myeloma is a rare neoplasm in cats. Common presenting signs (e.g., lethargy, anorexia, weight loss) usually are nonspecific. Two cats with multiple myeloma were presented with primary complaints of lameness; one had femoral osteolytic lesions, and the other likely had hyperviscosity syndrome. The cat with osteolytic lesions was treated with chemotherapy; the primary lesion responded, but the neoplasia metastasized.