Bone and bone marrow necrosis associated with the calf form of sporadic bovine leukosis.

The presence of neoplastic cells in the medullary cavity of bone may have various consequences including erosion of cortical bone, fat and marrow embolism, peripheral blood cytopenias, pathologic fracture, and necrosis of medullary bone and bone marrow elements.'-'O In man, infarction of bone is recognized to have many causes including intramedullary lymphoid tumors. * ,2 ,5,6 In this report, we describe multiple bone infarcts in six calves that had sporadic bovine leukosis. Each of these animals was presented individually with one of the following complaints: unthriftiness and inactivity, posterior ataxia, superficial lymph node enlargement, lameness, and/or respiratory distress. Both sexes (three male, three female) and various breeds (Simmental(3), Hereford (l), Holstein (I), not recorded (1)) were represented. The age range was 3 weeks to 8 months. At necropsy all animals had generalized lymph node enlargement, and all had a final diagnosis of sporadic bovine leukosis. Other organs which were involved in the neoplastic process included bone marrow (6), liver (4), kidney (3), spleen (3), and urinary bladder (1). Posterior ataxia in one animal was associated with a tumor causing spinal cord compression in the lumbar area. Three of the six animals had widespread petechial hemorrhages. All animals had variable sized areas of infarction involving the medullary cavity of vertebrae and long bones (Figs. 1-3). Typically these were pale areas that were often surrounded by a hemorrhagic zone. Ribs and cranial base were involved in two animals. Infarcts often