Spurious laboratory results associated with immunoglobulin M gammopathy in a dog with multiple myeloma.

Abstract

An 11 year old female-neutered Labrador presented for facial swelling. Clinicopathological abnormalities included hyperglobulinemia, azotemia, hypercalcemia, nonregenerative anemia, thrombocytopenia, and spurious hypoglycemia. Normoglycemia was subsequently confirmed using a cage-side analyzer (AlphaTRAK, Zoetis, UK). Serum and urine protein electrophoresis documented monoclonal (immunoglobulin M) gammopathy with Bence-Jones proteinuria. Computed tomography imaging revealed a monostotic osteolytic bone-lesion, and bone marrow cytology and histopathology documented plasmacytosis with multiple myeloma oncogene 1 / interferon regulatory factor 4 positivity, consistent with multiple myeloma. Infectious disease testing initially indicated seropositivity for Leishmania, Borrelia, and Anaplasma spp.; however, Leishmania PCR (splenic and bone marrow aspirates), and paired serological titers for Borrelia and Anaplasma were negative. Consequently, initial serological results were considered to be false positive because of paraproteinemia-associated assay interference. Chemotherapy (prednisolone and melphalan combination therapy) was initiated, but the dog was euthanased 30 days later because of the development of pericardial effusion. This is a report of spurious serological (and other laboratory) results occurring secondary to monoclonal gammopathy in a dog.

• Authors: Samantha C Loane, Daniel A Castillo, Anne-Lorraine D M Peschard, Harriet R Hall, Andre J Kortum
• Journal: Journal of veterinary internal medicine (J Vet Intern Med) Vol. 36 Issue 6 Pg. 2181-2186 (Nov 2022) ISSN: 1939-1676 [Electronic] United States
• PMID: 36125290 (Publication Type: Case Reports)
• Copyright: © 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.

Chemical References

• Immunoglobulin M
• Melphalan

Topics

• Female
• Dogs
• Animals
• Multiple Myeloma (complications, diagnosis, veterinary)
• Immunoglobulin M (therapeutic use)
• Melphalan (therapeutic use)
• Bone Marrow (pathology)
• Proteinuria (drug therapy, veterinary)
• Dog Diseases (diagnosis, drug therapy)