Surface immunoglobulin light chain-positive acute lymphoblastic leukemia of FAB L1 or L2 type: a report of 6 cases in adults.
Acute lymphoblastic leukemia (ALL) of B-cell lineage may be classified using the French-American-British (FAB) classification as L1, L2, or L3 type. L1 and L2 ALLs characteristically express terminal deoxynucleotidyl transferase (TdT) and are surface immunoglobulin (sIg)-negative. In contrast, L3 ALL is typically TdT-negative and sIg-positive. However, in a few large studies of children with ALL, sIg expression has been reported in less than 2% of L1 and L2 neoplasms. In these sIg-positive cases, IgM usually has been detected, with Ig light chain in a subset of tumors. Surface Ig expression in L1 or L2 ALL in adults is extremely rare; we found only 1 case report in the English literature. We report 6 cases of L1 or L2 ALL with an unusual immunophenotype arising in adults. In each tumor, the neoplastic cells expressed monotypic sIg light chain (4 lambda, 2 kappa) and TdT. Three tumors expressed CD34. Cytogenetic studies in 4 cases at diagnosis or relapse revealed no evidence of chromosomal translocations involving the c-myc locus, such as the t(8;14), t(2;8), or t(8;22). Three patients responded completely to chemotherapy and are alive; follow-up ranges from 18 to 57 months. Three patients died at 3, 13, and 14 months after diagnosis.
Vasef
M A
MA
Division of Pathology, City of Hope National Medical Center, Duarte, California, USA.
Brynes
R K
RK
Murata-Collins
J L
JL
Arber
D A
DA
Medeiros
L J
LJ
D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000378:metabolism*; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007621:Karyotyping; D008297:Male; D016133:Polymerase Chain Reaction; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013499:Surface Properties
D007147:Immunoglobulin Light Chains