Diagnosis and subclassification of follicle center and mantle cell lymphomas on fine-needle aspirates

Abstract

Cytologic distinction between follicle center lymphoma (FCL) and mantle cell lymphoma (MCL) is difficult with cytomorphology alone and requires immunophenotyping. The current study describes the distinction between follicle center and mantle cell lymphoma made with fine-needle aspiration (FNA) material. One hundred ten cases primarily diagnosed and classified on FNA material as centroblastic-centrocytic (CBCC) and centrocytic (CC) non-Hodgkin lymphomas (NHLs) (Kiel classification) were included in the study. An additional retrospective immunocytochemical analysis was performed on frozen cytospin preparations using the monoclonal antibodies Bcl-2, CD10, CD5, CD23, CD43, and immunoglobulin M. The initial diagnostic workup classified 106 cases as CBCC-NHL and 4 as CC-NHL. The immunophenotype Bcl-2(+), CD10(+/-), CD5(-), CD23(-/+), CD43(-) was observed in 93 of 106 previously reported CBCC NHLs. In 11 of 106 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 immunocytochemical 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-67) immunoreactivity was 16.3% and 17.5% in FCL and MCL, respectively. The revised cytopathologic diagnosis correlated significantly (P < 10(-9)) with the histology of 65 patients who underwent surgical excision biopsy. Subclassification of follicle-derived low grade NHL can be established with high accuracy on FNA material if cytomorphology is corroborated 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. Cancer (Cancer Cytopathol)