Immunological and ultrastructural observations on swine thymic lymphoma

A case of swine thymic lymphoma is described. A young pig had a mediastinal mass and bone marrow involvement and the microscopic findings showed peripheral blood involvement. The tumour was composed of small to medium sized lymphoid cells which formed rosettes with sheep erythrocytes and were characterized by narrow cytoplasmic bands, nuclear convolution and clustered dense bodies. Such structural and immunological features resembled those of human thymic lymphomas derived from thymic T-cells.