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

The diseases which chiefly pertain to the differential diagnosis of splenic lymphomas and leukemias primarily involving the red pulp have been separated into five histologic categories. These include the various forms of congestion, infections, benign and malignant histiocytic proliferations, leukemias and myeloproliferative disorders, and the rare nonhematopoietic tumors of the spleen. Many diseases with major involvement of the red pulp present as hypersplenism of unknown etiology. Accurate diagnosis is particularly dependent on an awareness of the specific histologic manifestations of malignant histiocytosis and the different leukemias in contrast to benign disorders, such as infectious mononucleosis which may simulate malignancy in the splenic red pulp. For each histologic category, therefore, the relevant morphologic features are reviewed, pathophysiologic mechanisms and clinical manifestations correlated, and criteria for differential diagnosis emphasized.