CD23 negative chronic lymphocytic leukemia of the tonsil: report of a case.

We present the case of atypical chronic lymphocytic leukemia presenting as a tonsillar mass in an elderly man. Histological examination of the tumor revealed diffuse submucosal infiltration by small lymphocytes. On flow cytometry, a monoclonal B lymphocytic population expressing CD5, CD19, lambda light chain, but not expressing CD10, CD23, or FMC7 activities, was observed. A diagnostic conundrum occurred with the demonstration on molecular cytogenetic analysis of the chromosomal translocation abnormality, t(11;14)(q13;q32). The diagnosis of CD23 negative chronic lymphocytic leukemia was made after further molecular studies failed to detect the bcl-1 gene rearrangement.