Surgical pathology of the spleen: an approach to the differential diagnosis of splenic lymphomas and leukemias. Part I. Diseases of the white pulp.

In order to facilitate diagnostic accuracy in the pathologic examination of the spleen, the differential diagnosis of the various splenic lymphomas and leukemias are divided into those diseases which primarily affect the white or red pulp. Enlargement of the splenic white pulp is due to either lymphoid hyperplasia, with or without the formation of germinal centers, or lymphomas and other lymphoproliferative disorders including chronic lymphocytic leukemia. Differentiation depends on recognition of germinal centers and the polymorphous nature of the lymphoid proliferation in reactive conditions, in comparison to the general monomorphous type of white pulp expansion found in the majority of lymphomas and lymphoproliferative disorders. Many of the reactive conditions are associated with a clinical hypersplenic state, while splenic lymphomas and lymphoproliferative disorders are frequently asymptomatic and discovered only at laparotomy. Macroscopic and microscopic evidence of enlargement of the white pulp may be absent in spleens of normal weight that are involved by lymphoma. In that situation, diagnosis requires meticulous examination of the white pulp for the demonstration of cytologic atypia.