Idiopathic Hemorrhagic Pericardial Effusion as a Precursor to Epicardial Lymphosarcoma in Three Cows

Abstract

A 2-year-old female Holstein heifer was referred for evaluation of acute onset brisket edema and jugular venous distension. The heifer was 223 days in milk and 139 days pregnant and had been producing milk at expected levels until the day before presentation. Physical examination at admission to the University of Wisconsin Veterinary Medical Teaching Hospital revealed a bright and alert individual with a rectal temperature of 100.6 F, and pulse and respiratory rates of 76 beats and 34 breaths per minute, respectively. Muffled heart sounds were present and both jugular veins were turgid, visibly distended, and displayed retrograde fill. An echocardiogram at admission using a 2.5–3.5 MHz phased array transducer from a right parasternal approach identified an approximately 8-cm distension of the pericardial sac by anechoic fluid that was evident during all phases of the cardiac cycle. Some thickening of the epicardial surface was noted with strands of more hyperechoic tissue floating on the epicardial surface with the ultrasonographic appearance of fibrin. Cardiac contractility appeared subjectively poor although functional cardiac measurements were not obtained because of the depth of pericardial fluid. A serum sample obtained at admission tested positive by both ELISA and AGID techniques for antibodies to the bovine leukosis virus (BLV). Pericardiocentesis yielded bloody fluid with a PCV of 14%, total protein concentration of 5.2 g/dL, and total nucleated cell count (TNCC) of 5.75 9 10/lL. The nucleated cells were comprised of 14% neutrophils, 64% small lymphocytes, and 22% macrophages. The lymphocytes were cytologically normal. Approximately 5.5 L of hemorrhagic pericardial fluid was removed through a 24 French chest tube placed in the left 5th intercostal space, decreasing the visible depth of pericardial fluid to approximately 2 cm. The heifer was given 0.1 mg/kg dexamethasone IV q24h for 3 days and underwent daily ultrasonographic assessment of pericardial fluid volume and subjective evaluation of cardiac function. By day 3 of hospitalization, minimal pericardial fluid remained (<10 mm) but focal areas of epicardial fibrin still could be seen. Jugular venous distension had resolved and the heifer’s heart rate was normal. It had normal appetite and milk production had improved. The heifer was returned to its farm of origin and continued to do well, producing 68 lb of milk at a subsequent test date approximately 50 days post discharge. Unfortunately, it was found dead approximately 100 days after discharge. Necropsy showed thickening of the epicardial surface of the heart with multiple fibrous attachments connecting the epicardial surface to the pericardium. The epicardial surface was matted with extensive areas of fibrosis admixed with fibrin and hemorrhage. Multiple thoracic lymph nodes were enlarged with similar multifocal white to tan infiltrates. Histologically, the epicardium was expanded with fibrosis and highly vascular papillary projections in which there were many atypical neoplastic lymphocytes alongside a mononuclear inflammatory infiltrate of small lymphocytes and plasma cells. The myocardium had areas of fibrosis but no neoplastic infiltrate. Histologically, lymphosarcoma was confirmed in the thoracic lymph nodes.