GENETIC-ANALYSIS OF SPLENIC LYMPHOMA WITH VILLOUS LYMPHOCYTES - A GROUPE FRANCAIS DHEMATOLOGIES CELLULAIRE (GFHC) STUDY

In order to characterize the genetic diversity in splenic lymphoma wit h villous lymphocytes (SLVL), we have undertaken cytogenetic and molec ular analyses of CCND1 expression and BCL1-IgH PCR rearrangement in 76 cases diagnosed predominantly on morphological criteria. Cytogenetic abnormalities were detected in 19/44 (43%) of cases, including in 16/2 5 (64%) of cases with an absolute lymphocytosis. Abnormalities include d those involving chromosome 14q32 (9/19, 47%), predominantly t(11;14) (q13;q32) (5/19, 26%), chromosome 3 (26%), predominantly 39, chromosom e 17p (26%) and trisomy 12 (3/19, 16%) and were thus suggestive of pat hogenetic diversity CCND1 was expressed in 8/30 (27%) cases, including in all t(11;14) cases, 5/10 (50%) CD5-positive cases and also in 3/20 (15%) CD5-negative cases. Three CCND1-positive SLVL demonstrated immu nophenotypic features similar to mantle cell lymphoma (MCL) but the ma jority differed in their CD5 negativity or CD23 positivity. BCL1-IgH r earrangement was only seen in 1/62 (2%) of cases overall and in none o f the t(11;14) cases, which demonstrated FISH breakpoints both centrom eric and telomeric to the BCL1/MTC, suggesting that, if genomic cluste ring exists in t(11;14) SLVL, it differs from MCL. Although CCND1 expr essing SLVL more commonly had marked lymphocytosis, they did not demon strate a more aggressive clinical course than their negative counterpa rts, demonstrating that the detection of CCND1 expression or of a t(11 ;14) should not suffice to alter diagnostic classification in the abse nce of other criteria.