Multicentric malignant Schwannoma in a crossbred cow.

Multicentric malignant Schwannoma in a crossbred cow is described. Multiple and solitary nodules of varying sizes were seen to be distributed throughout the body of the animal, mainly along the peripheral nerves supplying the muscles of the thoracic and abdominal regions and the skin. Multiple nodules were also observed in the hilus of the liver. The mediastinal lymph nodes were replaced by a large solitary tumorous mass. Multiple neoplastic linear cords with small nodules were observed on the pericardium. Histologically, the nodules showed mainly densely packed, spindle-shaped cells arranged in short interwoven bundles and whorls (Antoni type A pattern). Stellate, spindle-shaped and round or oval tumour cells proliferated haphazardly within the loose texture of a collagenous matrix (Antoni type B pattern). Immunohistochemically, in both Antoni type A and type B areas, neoplastic cells reacted with antibodies against S-100 protein. Based on the metastasis of the tumour to the lymph nodes and on histology, the neoplasm was diagnosed as a multicentric malignant Schwannoma.