LYMPH-NODE HISTOLOGY IN TYPICAL AND ATYPICAL CHRONIC LYMPHOCYTIC-LEUKEMIA

According to the French-American-British (FAB) proposal on the classif ication of chronic lymphoid leukemia (CLL), the disorder can be subdiv ided into typical and atypical CLL. We recently demonstrated the progn ostic significance of this subgrouping and based on these results we s uggested that typical and atypical CLL represent two closely related, but different entities. These results prompted us to investigate 42 pa tients diagnosed with CLL based on the results of lymph node biopsy in order to identify the histologic counterpart of the CLL variants. A f irst group of 14 cases showed a monomorphic proliferation of small rou nd lymphocytes associated with the occurrence of small pseudofollicles . All these cases were diagnosed as typical CLL on peripheral blood (1 3 cases) or bone marrow smear (1 case). The remaining 28 cases showed aberrant histologic features characterized by the presence of large nu mbers of paraimmunoblasts and prolymphocytes, forming very large pseud ofollicles, and/or by nuclear irregularities of the neoplastic cells, Based on peripheral blood smears (22 cases) or bone marrow smears (six cases), two cases showed no peripheral blood involvement, 21 cases we re diagnosed as atypical CLL, and five as typical CLL. From these data we can conclude that a histologic counterpart of the CLL variants rec ognized in the FAB proposal does exist; moreover, our data may explain reports on lymph node involvement by CLL composed of small cleaved ce lls and clarify the occurrence of pseudofollicles in cases described a s mantle cell lymphomas.