NODAL BENIGN AND MALIGNANT MONOCYTOID B-CELLS WITH AND WITHOUT FOLLICULAR LYMPHOMAS - A COMPARATIVE-STUDY OF FOLLICULAR COLONIZATION, LIGHT-CHAIN RESTRICTION, BCL-2, AND T(14-18) IN 39 CASES

As part of an effort to develop a better understanding of the relation ship between nodal monocytoid B-cell lymphomas (MBCLs) and follicular lymphomas (FLs) when they coexist (MBCL + FL) and to assess the validi ty of the morphological criteria for the latter diagnosis, we evaluate d follicular colonization, bcl-2 reactivity, light chain restriction, and the presence of t(14;18) in 14 benign lymph node specimens contain ing benign monoclonal B cells (MBCs), in eight nodal specimens of pure MBCL, and in 17 nodal specimens of MBCL coexisting with FL (MBCL + FL ). Follicular colonization by malignant MBCs was observed in six speci mens of pure MBCL and in 13 specimens of MBCL + FL. Benign MBCs did no t express bcl-2 by immunohistological methods in 11 of 12 benign speci mens. In contrast, weak reactivity for bcl-2 was detected in malignant MBCs in four of five specimens of pure MBCL and in the MBCL component in 13 of 15 specimens from the MBCL + FL group. In the FL component o f 13 specimens, the bcl-2 was strongly positive. Identical light chain restriction was detected by immunohistological methods in both the FL component and the MBCL component in 15 specimens of MBCL + FL. Polyme rase chain reaction analysis did not detect the t(14; 18) translocatio n in any of 10 benign specimens or any of six evaluable pure MBCL spec imens. In contrast, the translocation was detected in whole sections f rom eight of 12 specimens of MBCL + FL. Thus, on the one hand, the hig h incidences of follicular colonization and the coexistence of MBCL an d FL as well as the identical light chain restriction in MBCL and FL c omponents of MBCL + FL cases suggest that possibly these are related c losely when they coexist On the other hand, the bcl-2 and t(14;18) dat a cannot be used as evidence in support of a close relationship. Copyr ight (C) 1995 by W.B. Saunders Company