Splenic Marginal Zone Lymphoma Can Transform to a Clinical Picture Resembling B-Cell Prolymphocytic Leukemia: A Morphological, Immunophenotypical and Cytogentic Study.
L Jeffrey Medeiros, Daniela Hoehn. UT MD Anderson Cancer Center, Houston, TX
Background: B-cell prolymphocytic leukemia (B-PLL), first described by Galton et al (Br J Haematol 1974; 27: 7-23), is a disease that has undergone extensive refinement in the past decade. This is attributable to the clear definition of the prolymphocytoid variant of chronic lymphocytic leukemia in the World Health Organization (WHO) classification and the recognition of the prolymphocytoid or nucleolated variant of mantle cell lymphoma. B-PLL is currently a rare disease, the etiology and pathogenesis being incompletely understood.
Design: We describe 3 cases of splenic marginal zone lymphoma (SMZL) who underwent transformation to leukemic phase with numerous prolymphocytes resembling, in part B-PLL. The clinical data were obtained from the medical records. Routinely stained slides of spleen and blood and bone marrow were reviewed. In all cases immunophenotypic studies were performed using either flow cytometry or immunohistochemistry. Conventional cytogenetic analysis was performed on bone marrow aspirate material of 1 patient.
Results: The study group included 3 adults, 2 women and 1 man, ranging in age from 62 to 82 years. Each patient presented with leukocytosis (normal range 4-11 x 109/L) with a count of 11.9, 75.1, and 131.5 x 109/L. Prolymphocytes in the blood smear were 79%, >55%, and 86%, respectively. The differential count showed 55 to 86% prolymphocytes. Bone marrow aspiration and biopsy showed extensive involvement by lymphoma. All patients had prominent splenomegaly and splenectomy revealed a spleen size ranging from 1500 to 2466 grams. Each spleen was involved by multiple, tan-white, firm nodules, histologically composed of small lymphoid cells with abundant, pale cytoplasm, a subset of which had prominent nucleoli. Flow cytometry immunophenotyping analysis in all cases showed a monotypic B-cell population positive for surface Ig, pan-B-cell antigens, CD11c, and FMC7, and negative for CD3, CD5, and CD10. Cytogenetic analysis in 1 case showed del(7q22).
Conclusions: We conclude that SMZL can undergo transformation to a leukemic phase with numerous prolymphocytes in the blood closely resembling B-PLL. These cases suggest that prolymphocytic transformation of SMZL, and possibly other types of marginal zone lymphomas, accounts for a subset of cases that remain within the B-PLL category. We further suggest that the category of B-PLL as currently defined in the WHO classification is shrinking, perhaps eventually to its extinction, as we improve our ability to classify B-cell leukemias.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 172, Wednesday Morning