B-Lymphoblastic Leukemia in Patients With Chronic Lymphocytic Leukemia: A Report of Four Cases.

Chakhachiro, Zaher; Yin, C Cameron; Abruzzo, Lynne V; Aladily, Tariq N; Barron, Lynn L; Banks, Haley E; Thomas, Deborah A; Keating, Michael et al. · Am J Clin Pathol · 2015

case_report · Level V

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Abstract

B-lymphoblastic leukemia (B-LBL) arising in patients with chronic lymphocytic leukemia (CLL) is exceedingly rare and poorly characterized. We describe four patients with CLL and concurrent or subsequent B-LBL diagnosed by morphologic, immunophenotypic, cytogenetic, and molecular analysis and reviewed the literature. In three patients, B-LBL followed CLL by 5 to 15 years, and in one patient, B-LBL was diagnosed simultaneously with CLL. In all cases, the CLL had a typical immunophenotype, and the B-LBL blasts showed an immature B-cell immunophenotype with expression of CD10, CD19, and TdT and absence of surface immunoglobulin. In two patients, B-LBL blasts harbored t(9;22)(q34;q11.2)/BCR-ABL1. We sequenced the IGHV genes in both CLL and B-LBL in two patients and showed that IGHV usage differed. Our data suggest that at least some cases of B-LBL arising in patients with CLL are independent, secondary neoplasms rather than a manifestation of histologic transformation.

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