[Question of differential diagnosis in a case of chronic B-cell lymphopathy]

We have reported the case of a woman aged 76 years suffering from pancytopenia, splenomegaly, relative lymphocytosis, lymphocytes with villous projection in the peripheral blood. On the basis of membrane phenotype, cytochemistry, ultrastructural examination of blood and marrow lymphocytes, differential diagnosis was between chronic lymphatic leukemia (CLL), CLL of mixed cell type, hairy cell leukemia (HCL), HCL variant, splenic lymphoma with circulating villous lymphocytes (SLVL), Non-Hodgkin lymphoma of mantle zone (NHL). The application of morphologic and immunological methods has reinforced the value of cytomorphology and has proved advantageous in increasing our understanding of the heterogeneity of B CLL itself. A new classification of chronic B leukemias has been proposed on the basis of clinical, cytomorphological, histological, cytochemical, immunological criteria: CLL; CLL of mixed cell type including cases with more than 10% and less than 55% prolymphocytes (CLL/P) and a less well defined form with pleomorphic lymphocytes (CLL/P) and a less well defined form with pleomorphic lymphocytes but less than 10% prolymphocytes; prolymphocytic leukemia (PLL); hairy cell leukemia (HCL); HCL variant; splenic lymphoma with circulating villous lymphocytes (SLVL); leukemic phase of NHL (follicular lymphoma, intermediate or mantle zone lymphoma, and others); lymphoplasmacytic lymphoma; plasma cell leukemia. Even if the application of cytomorphological and immunological criteria has increased our knowledge of the heterogeneity of chronic B leukemias, in some cases, as in the one reported, exact classification may be very difficult. However, on the basis of clinical and laboratory criteria this case can be classified as SLVL, notwithstanding some discrepancies of the immunophenotype.