Multiple Myeloma

Multiple myeloma is a neoplastic proliferation of plasma cells with infiltration of bone marrow by transformed malignant cells. It is diagnosed mainly in dogs older than nine years. Disease effects result from infiltration of bone marrow and other organs, including the eye, and from production of paraprotein responsible for hyperviscosity syndrome.

Hyperviscosity causes neurologic and cardiovascular abnormalities and retinopathy. Paraprotein may also contribute to thrombocytopenia and bleeding tendency. Patients with multiple myeloma often have anemia, pancytopenia, hypercalcemia, renal failure, and susceptibility to secondary bacterial infection. Ophthalmic examination may show tortuous retinal vessels and intraocular hemorrhage, most commonly in the posterior segment. These changes, together with retinal degeneration, may result in retinal detachment.

Treatment

Diagnosis includes complete blood count, serum biochemistry, and urinalysis. Serum and urine protein electrophoresis may be useful. Radiographs of the abdomen, spine, and limbs and ultrasonography of internal organs may assist evaluation. Myeloma is confirmed by bone-marrow aspiration and cytologic examination. Treatment is complex and may include radiation, chemotherapy, plasmapheresis, analgesics, and medications to reduce hypercalcemia.

Multiple myeloma and retinal detachment in a dog with focal intraretinal hemorrhages. The changes developed because of blood hyperviscosity and tissue hypoxia.

Related in-depth guide

Adapted from the Atlas of Ocular Diseases in Dogs and Cats by Dr. Siniša D. Grozdanić and colleagues. © Animal Eye Consultants of Iowa. The text and clinical images on this page are original content from the authors' own clinical practice and research, and may not be reproduced, distributed, or repurposed without permission.

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