Concomitant multiple myeloma and probable phaeochromocytoma in a cat.

CASE SUMMARY: Herein a drug-resistant IgG-lambda-type multiple myeloma associated with probable phaeochromocytoma in a cat is described. A 12-year-old cat presented with weakness, weight loss, progressive blindness and open-mouth breathing, in addition to polyuria and polydipsia of 2 months' duration. Abdominal ultrasonography revealed a left adrenal mass. Phaeochromocytoma was suspected on the basis of cytology and was associated with systemic hypertension. Biochemistry showed hyperproteinaemia. Serum protein electrophoresis revealed a narrow spike in the gamma region, identified as IgG lambda type at immunoelectrophoresis. Bone marrow cytology revealed an infiltrate with numerous mature plasma cells. The cat was resistant to two different drugs for multiple myeloma and was euthanased 6 months later because of anorexia and persistent poor general condition.

RELEVANCE AND NOVEL INFORMATION: This is the first clinical description of multiple myeloma associated with a suspected phaeochromocytoma in a cat.