Primary cardiac lymphoma in a 10-week-old dog.

A 10-week-old miniature dachshund presented with acute onset of weakness. Electrocardiography showed sustained ventricular tachycardia, and thoracic and abdominal radiography revealed pleural and peritoneal effusion. Echocardiography revealed severely hypokinetic left and right ventricles. Thoracocentesis and abdominocentesis and subsequent transfer to an oxygen chamber yielded no clinical improvement, and the dog died about 1 hr after admission. Gross examination of a longitudinal section through the entire heart revealed poorly demarcated focal or patchy areas of grayish-white tissue infiltrating extensively into the myocardium. Histologically, these lesions were consistent with infiltrative proliferation of neoplastic lymphoid cells. Immunohistochemical staining confirmed the diagnosis of primary cardiac lymphoma (PCL) of T-cell origin. There have been no previous reports of such young dogs with PCL.