Clinical and Morphologic Features of B-Cell Small Lymphocytic Lymphoma With De 1 ( 6 ) ( q 2 lq 23 )

Deletions of the long arm of chromosome 6 have been described in acute and chronic lymphocytic leukemia (ALL and CLL) and prolymphocytic leukemia (PLL), and have been associated with t(14;18)(q32;q21) in non-Hodgkin's lymphoma (NHL). Of 55 cases of small lymphocytic (sm lym) NHL, deletions of 6(q2lq23) were the most common recurring cytogenetic abnormality. Among 14 sm lyrn NHL with de1(6)(q21q23), this abnormality occurred as a solitary change in 3 cases. Each of these 3 cases, and 5 additional cases with del(6q) and other abnormalities, showed atypical larger forms with the morphologic appearance of prolymphocytes or paraimmunoblasts in the peripheral blood. In comparison, of the 11 cases without del(6q) and circulating abnormal cells, prolymphocytoid forms were observed in 4 cases (P c .001). Of the 31 sm lyrn without del(6q). trisomies of chromosomes 3, 12, or 18, or t(11;14)(q13;q32) occurred in greater than 10% of cases. Proliferation centers or infiltration by larger forms were observed in similar proportions of