Linfossarcoma de células B multicêntrico em uma ovelha

RESUMO

Background:     Lymphosarcoma is a malignant tumor from tumoral cells similar to lymphocytes and its spontaneous development in small ruminants is unusual in Brazil. In cattle, the lymphosarcomas are often associated with infection by bovine leukemia virus (BLV), although sheep are considered as a very susceptible specie to BLV. Spontaneously lymphosarcoma is rare and in most cases it is observed in apparently healthy animals in slaughterhouses. There is no report of this tumor in sheep in southern Brazil. We describe a case of spontaneous multicentric B-cells lymphosarcoma in an ewe. Case In June 2007, a 4-years-old mixed breed ewe was necropsied after clinical signs as anorexia, weight loss and death in few weeks. This ewe was purchased in September 2006 with another 44 sheep, most females of the same age. Dairy cattle were also raised together with sheep at the same farm. Fragments of liver, lung, spleen, kidneys, brain and parotid lymph node were sent to the Veterinary Pathology Laboratory - Universidade Federal de Santa Maria, Brazil, for histopathological evaluation. Multiply white to yellow nodules, with 0.5 to 2 cm of diameter, were observed in the liver, kidneys, and the parotid lymph node. The nodules were soft and some coalesced and infiltrating the hepatic parenchyma. The kidneys nodules were similar to those of the liver but prominent in the capsule. They were o