CD5-GRADE MARGINAL ZONE B-CELL LYMPHOMAS WITH LOCALIZED PRESENTATION(LOW)

Marginal zone B-cell lymphomas (MZBCLs) are low-grade lymphomas that c haracteristically lack CD5 expression. However, rare cases of MZBCL ha ve been described in which the lymphomatous B cells coexpress CD5 (CD5 (+) MZBCL). In 7 of 9 reported CD5(+) MZBCLs, there was evidence of wi despread disease. We report four additional cases of CD5(+) MZBCL. Thr ee cases were low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) involving the lungs, the conjunctiva (bilateral), and t he uterus. The remaining case represented a monocytoid B-cell lymphoma involving a posterior cervical lymph node. Southern blot hybridizatio n did not show rearrangements of bc11 or bc12 in the three cases analy zed. All four patients had localized disease and normal peripheral blo od counts. Staging of bone marrow biopsies from three patients did not show evidence of bone marrow involvement. The remaining patient had b ilateral conjunctival lesions that were present for 15 years without p rogression. These four additional cases of CD5(+) MZBCL show that this group of low-grade B-cell lymphomas occasionally may exhibit an atypi cal phenotype. Furthermore, in this study, the CD5(+) MZBCLs were clin ically localized at presentation, in contrast to most other reported c ases, which have had dissemination to bone marrow or peripheral blood.