Elastic mantle cell leukemia: An unusual presentation of blastic mantle cell lymphoma

Six patients had blood and bone marrow manifestations characterized by the presence of morphologically immature or blastic B-lineage lymphoid cells ex pressing CD5 antigen. The median patient age was 70 years, and the male-to- female ratio was 5:1. The presence or degree of lymphadenopathy and splenom egaly was variable among this group at staging evaluation, although two pat ients did not have these features. One patient had an antecedent diagnosis of classical nodal mantle cell lymphoma, without prior morphologic blood or bone marrow involvement. Other patients lacked a history of underlying lym phoproliferative disorders. The median white blood cell count was 120 x 10( 9)/L. Most patients had thrombocytopenia, whereas only one patient had neut ropenia at presentation. Leukemic peripheral blood cells in these six cases were small to medium in size with fine or granular nuclear chromatin and s mall or inconspicuous nucleoli. The pattern of marrow involvement was inter stitial or diffuse, with cells showing immature nuclear features resembling acute leukemia or blastic lymphoma All tumors demonstrated a consistent im munophenotype of B-cell lineage, surface immunoglobulin positivity, and CD5 antigen expression. The progenitor cell-associated markers CD34 and TdT we re not expressed, and CD23 antigen was either negative (three of four cases ) or only weakly present tone of four cases). The presence of a karyotypic t(11;14)(q13;q32) was documented in one tumor, whereas two other cases had BCL-1 gene rearrangements by either polymerase chain reaction or Southern b lot analysis. Cyclin D1 mRNA overexpression was noted in three of four case s tested. This patient group was characterized by very poor overall surviva l (median, 3 months; range, 0.5 to 6 months). The aggregate clinical, patho logic, and genetic data in these unusual cases are consistent with de novo or predominant leukemic presentations of blastic mantle cell lymphoma. Accu rate diagnosis in such cases is greatly facilitated by cytogenetic studies or the demonstration of BCL-1/cyclin D1 abnormalities.