Multiple Myeloma in Horses, Dogs and Cats: A Comparative Review Focused on Clinical Signs and Pathogenesis

Multiple myeloma (MM) or plasma cell myeloma is a neoplastic proliferation of plasma cells that primarily involves the bone marrow but may originate from extramedullary sites [1-4]. Although it is uncommon in veterinary medicine, it has been reported in several species, in‐ cluding cats, dogs and, horses [1,3,5-10]. The frequency of MM in cats is slightly <1% of all malignant neoplasms. Canine MMs account for only 0.3% of all malignancies in dogs. MMs account approximately 2% of all hematopoietic neoplasms in both dogs and cats [4]. Most of the reports in the literature are limited to 1 to 16 case studies [4,11-16]. However, in a recent report regarding the incidence of bone disorders diagnosed in dogs, MM was the second most frequently diagnosed neoplastic condition in canine bone marrow [17].