Diagnosis and subclassification of follicle center and mantle cell lymphomas on fine-needle aspirates - A cytologic and immunocytochemical approach based on the revised European-American lymphoma (REAL) classification

BACKGROUND. Cytologic distinction between follicle center lymphoma (FCL) an d mantle cell lymphoma (MCL) is difficult with cytomorphology alone and req uires immunophenotyping. The current study describes the distinction betwee n follicle center and mantle cell lymphoma made with fine-needle aspiration (FNA) material. METHODS. One hundred ten cases primarily diagnosed and classified on FNA ma terial as centroblastic-centrocytic (CBCC) and centrocytic (CC) non-Hodgkin lymphomas (NHLs) (Kiel classification) were included in the study. An addi tional retrospective immunocytochemical analysis was performed on frozen cy tospin preparations using the monoclonal antibodies Bcl-2, CD10, CD5, CD23, CD43, and immunoglobulin M. RESULTS. The initial diagnostic workup classified 106 cases as CBCC-NHL and 4 as CC-NHL. The immunophenotype Bcl-2(+), CD10(+/-), CD5(-), CD23(-/+), C D43(-) was observed in 93 of 106 previously reported CBCC NHLs. In 11 of 10 6 cytospin preparations, neoplastic B cells expressed the CD5 pan T marker and, as a group, showed the pattern Bcl (+/-), CD10(-/+), CD5(+), CD23(-), CD43(+), which is considered typical of MCL. Based on the additional immuno cytochemical data, all but 2 of the tumors were reclassified as FCL (n = 93 ) and MCL (n = 15). The mean proliferation fraction measured by MIB-1 (Ki-6 7) immunoreactivity was 16.3% and 17.5% in FCL and MCL, respectively. The r evised cytopathologic diagnosis correlated significantly (P < 10(-9)) with the histology of 65 patients who underwent surgical excision biopsy. CONCLUSIONS. Subclassification of follicle-derived low grade NHL can be est ablished with high accuracy on FNA material if cytomorphology is corroborat ed by a complete immunophenotypic analysis, which can be performed on both fresh and frozen stored cytospin material. The currently used criteria can be applied to aspirated cells for a conclusive cytopathologic diagnosis of MCL, which is of great clinical importance. (C) 1999 American Cancer Societ y.