SPLENIC MARGINAL ZONE CELL LYMPHOMA ASSOCIATED WITH CLONAL B-CELL POPULATIONS SHOWING DIFFERENT IMMUNOGLOBULIN HEAVY-CHAIN SEQUENCES

Splenic marginal zone cell lymphomas (SMZCLs) are low-grade B-cell lym phomas that usually present with massive splenomegaly and subtle (subl eukemic) peripheral blood involvement. Polymerase chain reaction (PCR) analysis of peripheral blood from a patient with subleukemic SMZCL sh owed evidence of two clonal immunoglobulin heavy chain (IgH) gene rear rangements. IgH PCR analysis of DNA derived from the patient's splenic neoplasm demonstrated a single clonal IgH rearrangement, which had a different electrophoretic mobility from either of the two PCR products detected in the patient's peripheral blood. Additional characterizati on of these PCR products by DNA sequencing demonstrated two independen t IgH rearrangements in the peripheral blood, one of which used IgH jo ining region 6c (J(H)6c) and the other J(H)4. A different IgH rearrang ement was present in the splenic tumor, which used J(H)4a. No sequence s from the splenic neoplasm were detected in the peripheral blood and vice versa This case illustrates that PCR might reveal monoclonal popu lations in peripheral blood unrelated to the presence of lymphoma in o ther anatomic compartments.