Cytogenetic, interphase, and multicolor fluorescence in situ hybridization analyses in primary plasma cell leukemia: a study of 40 patients at diagnosis, on behalf of the Intergroupe Francophone du Myélome and the Groupe Français de Cytogénétique Hématologique.

Primary plasma cell leukemia (PCL) is a rare plasma cell malignancy. Consequently, few large reports have been published. Presented is a cytogenetic analysis of 40 patients with primary PCL compared with 247 newly diagnosed patients with stage III multiple myeloma (MM). Cytogenetic abnormalities were observed in 23 of 34 patients, with usually complex hypodiploid or pseudodiploid karyotypes. Analysis of rearrangements of the 14q32 region revealed significant differences with high cell mass MM-a higher incidence of t(11;14) (33% vs 16%; P <.025) and of t(14;16) (13% vs 1%; P <.002) though incidences of t(4;14) were identical and a higher incidence of monosomy 13 (68% vs 42%; P =.005). Hypodiploid karyotypes and monosomy 13 may explain, at least in part, the poorer prognosis of primary PCL. In contrast, significantly longer survival was observed in patients displaying t(11;14) in comparison with those lacking this translocation (P =.001).