Mantle Cell Lymphoma/Leukemia in Bone Marrow: Lacking Evidence of t(11;14)

Nam, Myung Hyun; Woo, Hee Yeon; Park, Quehn; Kim, Sun Hee; Ko, Young Hyeh; Ree, Howe J; Kim, Won Seog; Lee, Hong Gee; Park, Keun Chil

Abstract

BACKGROUND
Mantle cell lymphoma/leukemia (MCL) is a distinctive disease entity that has been characterized by specific histopathologic, immunologic, and cytogenetic features. The characteristic cytogenetic abnormality of MCL is t(11;14)(q13;q32), that results in cyclin D1 overexpression. We have experienced 12 MCL cases with bone marrow involvement that were lacking evidence of t(11;14). We tried to review the cases.
METHODS
We reviewed the bone marrow findings, immunophenotypic, cytogenetic studies including fluorescent in situ hybridization (FISH) analysis using IGH/CCND1 probes and medical records of 12 patients that were diagnosed with MCL based on immunophenotypic results during the period 1997 to 2001.
RESULTS
The patients had a median age of 63 (50-70) years with male-to-female ratio of 3:1. All patients showed hepatosplenomegaly with varying degrees of peripheral blood involvement (2-93%), and lymphocytosis was found in 7 cases. Other presenting features were palpable lymph nodes (83%) and B symptoms (25%). The malignant cells were quite heterogenous in morphology from centrocytic to blastic variants. Most cases showed typical immunophenotypes-expression of CD19, bright CD20, FMC7, CD5 and bright-light chains with negative CD23. Immunohistochemical staining with cyclin D1 on marrow biopsies showed mostly negative results. Among the eleven cases in which cytogenetic studies were possible, four cases showed complex karyotypes, and three that involved 14q32. Strikingly, no one showed t(11;14) in G-banding analysis and only 2 cases showed IGH/CCND1 rearrangement by FISH. CONCLUSTIONS: Most MCL cases with typical immunophenotypic findings did not show evidence of specific cytogenetic features. Although further workups for molecular pathogenesis and clinical follow-up of the above cases need to be done, we suggest a new disease entity, t(11;14)-negative MCL.