BONE-MARROW INVOLVEMENT IN LARGE-CELL LYMPHOMA - PROGNOSTIC IMPLICATIONS OF DISCORDANT DISEASE

Discordant lymphomas are those in which two different histologic subty pes of non-Hodgkin's lymphoma are present simultaneously in the same p atient at two or more separate disease sites. Discordance usually invo lves a lower grade follicular lymphoma in one anatomic site and a high er grade diffuse lesion elsewhere. A common type of discordance is see n in patients with a primary diagnosis of diffuse large-cell lymphoma (DLCL) who demonstrate bone marrow involvement by a lower grade lesion , such as a small cleaved cell or mixed small cleaved and large cell l ymphoma. This study was undertaken to assess retrospectively the clini cal implications of such bone marrow involvement, as well as the possi ble biologic mechanisms. Of the 59 DLCL cases studied, 20 (33.9%) show ed evidence of bone marrow involvement, 14 of which were discordant (7 0%). The most significant findings included the following: Overall tre atment responses and survivals in discordant patients with predominant ly small cleaved cells in the marrow were similar to those in patients with no marrow involvement (mean survivals, 47.7 and 49 months, respe ctively), and were significantly longer than in patients with concorda nt marrow involvement (mean survival, 13.1 months, P < .05). Patients with discordant marrow infiltrates composed of a mixed cell population tended to do as poorly as those with concordant involvement. No clear -cut pattern of relapse in discordant patients was found, but persiste nce of small cleaved cells in some was reminiscent of lower grade B-ce ll lesions. Other features associated with lower grade lesions include d older age, Less incidence of central nervous system involvement, and lesser extent and proportion of marrow infiltration. Finally, in appr oximately half the cases with discordant involvement, lymphoma was pre sent unilaterally, emphasizing the need to perform bilateral biopsies for staging.