Infiltrative cardiomyopathy responsive to combination chemotherapy in a cat with lymphoma.

A 3-year-old castrated male domestic shorthair cat had renal lymphoma and infiltrative cardiomyopathy, both of which responded to combination chemotherapy. Diagnosis was made on the basis of results of renal biopsy and echocardiography. Cardiac lesions included hypertrophy of the left ventricular free wall and interventricular septum, ventricular hypokinesis, and diminishment of the left ventricular chamber. Cytologic evaluation of pericardial fluid did not contribute to a diagnosis. Combination chemotherapy resulted in rapid improvement of renomegaly and cardiac structure and function. Although it might be assumed that the myocardial infiltration was attributable to metastatic lymphoma, histologic diagnosis of the heart disease was not established.