Question of the Day

This is multiple myeloma (MM), a malignancy of plasma cell origin. Malignant plasma cells arise from bone marrow and produce immunoglobulins (Ig), resulting in hyperglobulinemia. Hyperglobulinemia causes hyperviscosity and many of the clinical signs seen with MM.

Clinical signs include lethargy, weight loss, bone pain or fractures, CNS signs, capillary bleeding, visual disturbances (due to retinal hemorrhage), organomegaly, and heart murmurs (due to hyperviscosity).

Dx requires two or more of the following:

– Monoclonal gammopathy on serum electrophoresis

– Bence Jones proteinuria

– Lytic bone lesions on radiographs

– Plasma cell infiltration of the bone marrow

Here is more useful info on immunoglobulins from Cornell’s eClinPath website.

Ref: Cote, Clinical Veterinary Advisor: Dogs and Cats, 4^th ed., pp. 663-5. Image courtesy, Seth Chapman, DVM, MS, DACVP.