Non-Hodgkin's lymphoproliferative disorders involving the spleen.

One hundred eight splenectomy specimens involved by lymphoid neoplasms were studied to assess the frequency and pattern of involvement of the various disease groups. Cases were classified by the Working Formulation as well as by the Revised European-American classification of lymphoid neoplasms. Including the more recently described disease entities, large cell/immunoblastic lymphomas were the most common neoplasm, both primarily and secondarily, to involve the spleen (33.3% of all cases). The next most common lymphoid neoplasm to involve the spleen was chronic lymphocytic leukemia/ small lymphocytic lymphoma, found in 19.4% of cases, followed by follicular center cell lymphoma (13.0%), lymphoplasmacytoid lymphoma (9.3%), splenic marginal zone lymphoma (8.3%), mantle cell lymphoma (6.5%), and hairy cell leukemia (6.5%). The remaining 3.7% of cases included T-cell proliferations and one difficult-to-classify mixed cell lymphoma. More than 95% of the cases could be placed into one of three morphologic patterns of splenic involvement, i.e., 57.4% of spleens were involved by predominantly white pulp disease, 20.4% by predominantly nodular disease, without a predilection for white or red pulp, and 17.6% by predominantly red pulp disease. Although the white pulp and nodular patterns were primarily, but not exclusively, B-cell disorders, specimens with predominantly red pulp disease included all of the cases of hairy cell leukemia, as well as cases of both B- and T-cell lymphomas.