Cytomorphologic, immunocytochemical, and nucleic acid flow cytometric study of 50 lymph nodes by fine‐needle aspiration. Comparison with results obtained by subsequent excisional biopsy

Fifty patients with clinically suspected or previous diagnosis of lymphoma underwent fine‐needle aspiration (FNA) and subsequent excisional biopsy of their lymph nodes. Results of cytologic diagnosis made from the direct smears in conjunction with immunocytochemical study of cytospin preparations and nucleic acid flow cytometric study (FCM) were compared with the results obtained from histologic sections, cryostat–immunohistochemical study, and nucleic acid FCM performed on resected lymph nodes. This study demonstrates (1) results of immunocytochemical and DNA–FCM analysis of FNA‐derived material are comparable in the majority of cases to those obtained from surgical specimens, (2) immunostaining of cytospin preparations for immunoglobulin (Ig) gives less background staining and in certain cases is easier to interpret than when performed on frozen sections, and (3) monotypia in FNA in conjunction with cytomorphologic study is 100% specific for lymphoma, and polytypic staining for Ig does not exclude HD, T‐cell lymphoma, or B‐cell malignancy focally involving a lymph node.