Abstract
Lymphomas showing follicular proliferation in two cows were studied immunohistochemically. Case 1 showed severe leukemia and a positive antibody response to bovine leukemia virus (BLV). Histologically, numerous neoplastic follicular structures were observed in the lymph nodes and spleen. Case 2 showed a slightly increased percentage of peripheral lymphocytes and a negative antibody response to BLV. Neoplastic follicular structures in the spleen and lymph nodes were somewhat smaller than those of case 1. The neoplastic cells were medium-sized lymphoid cells in both cases. Under an electron microscope, the nuclei of neoplastic cells in case 1 were mostly oval in shape, while neoplastic cells in case 2 had cleaved nuclei. Immunohistochomically, intracytoplasmic immunoglobulins were negative in the neoplastic cells in both cases. Follicular dendritic reticular cells decreased in number in the neoplastic follicles. It is considered that these neoplastic cells may originate from follicular center cells.
