Progression of a Solitary, Malignant Cutaneous Plasma-Cell Tumour to Multiple Myeloma in a Cat
Case Report Progression of a solitary, malignant cutaneous plasma-cell tumour to multiple myeloma in a cat A. Radhakrishnan1, R. E. Risbon1, R. T. Patel1, B. Ruiz2 and C. A. Clifford3 1 Mathew J. Ryan Veterinary Hospital of the University of Pennsylvania, Philadelphia, PA, USA 2 Antech Diagnostics, Farmingdale, NY, USA 3 Red Bank Veterinary Hospital, Red Bank, NJ, USA Abstract An 11-year-old male domestic shorthair cat was examined because of a soft-tissue mass on the left tarsus previously diagnosed as a malignant extramedullary plasmacytoma. Findings of further diagnostic tests carried out to evaluate the patient for multiple myeloma were negative. Five Keywords hyperproteinaemia, months later, the cat developed clinical evidence of multiple myeloma based on positive Bence monoclonal gammopathy, Jones proteinuria, monoclonal gammopathy and circulating atypical plasma cells. This case multiple myeloma, pancytopenia, represents an unusual presentation for this disease and documents progression of an plasmacytoma extramedullary plasmacytoma to multiple myeloma in the cat. Introduction naemia, although it also can occur with IgG or IgA Plasma-cell neoplasms are rare in companion ani- hypersecretion (Matus & Leifer, 1985; Dorfman & mals. They represent less than 1% of all tumours in Dimski, 1992). Clinical signs of hyperviscosity dogs and are even less common in cats (Weber & include coagulopathy, neurologic signs (dementia Tebeau, 1998). Diseases represented in this category and ataxia), dilated retinal vessels, retinal haemor- of neoplasia include multiple myeloma (MM), rhage or detachment, and cardiomyopathy immunoglobulin M (IgM) macroglobulinaemia (Dorfman & Dimski, 1992; Forrester et al., 1992). and solitary plasmacytoma (Vail, 2001). These con- Coagulopathy can result from the M-component ditions can result in an excess secretion of Igs interfering with the normal function of platelets or (paraproteins or M-component) which produce a clotting factors.
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