Multicentric T-cell lymphoma accompa- nied by infiltration of the peripheral and central nervous system in a fattening pig.

Multicentric lymphomas, usually of B-cell origin, are rather common neoplasms in pigs, which usually affect lymph nodes and different organ systems. An uncommon manifestation of malignant lymphoma represents neoplastic peripheral nerve involvement, which has been reported in human medicine. So far, only single cases of lymphoma with manifestation in peripheral nerves (known as neurolymphomatosis) without leukemic conversion have been mentioned in different animal species others than swine. The present case report describes the occurrence of a multicentric T-cell lymphoma in a fattening pig with marked leukocytosis. The pig was presented with symptoms of lethargy, weight loss, and fever. Bone marrow aspirate contained all stages of granulocytic and erythrocytic precursors, and a remarkable large number of eosinophiles and undifferentiated blasts. At necropsy, the carcass showed generalized lymphadenopathy and severe hepatosplenomegaly. Histological findings included neoplastic round cell infiltrations in lymph nodes, bone marrow, tonsils, lung, spleen, liver, kidneys, urinary bladder, small and large intestine, and meninges. Additionally, neoplastic cells were present in the sciatic and medial plantar nerve of the left hind leg. The diagnosis T-cell lymphoma was confirmed immunohistochemically. To the author's knowledge, this work represents the first report of peripheral nerve involvement in a pig with multicentric T-cell lymphoma accompanied by CNS involvement and leukemia.