To evaluate the usefulness of polymerase chain reaction analysis of translocations involving the bcl-1 and bcl-2 genes in variants of CD5-positive B-cell lymphomas, we analyzed four cases classified as the paraimmunoblastic variant of small lymphocytic lymphoma. This neoplasm, originally identified as an aggressive, diffuse, B-lineage lymphoma related to small lymphocytic lymphoma, can be confused with variants of mantle cell lymphoma (an immunophenotypically and morphologically similar neoplasm). No translocations involving bcl-2 and the immunoglobulin heavy chain gene were identified; two cases had translocations involving the bcl-1 and the immunoglobulin heavy chain genes. The frequency of finding this translocation suggests that these categories of neoplasms might be extremely difficult to distinguish or that a closer relationship between these neoplasms exists than was initially proposed.