Diagnosis of lymphoid lesions using cytomorphology and flow cytometry

Flow cytometry (FC) has proven useful in the evaluation of non Hodgkin’s lymphomas (NHL) on samples obtained by fine needle cytology (FNC).1-3 Objective of this study is to evaluate the application of FC and FNC to the diagnosis and sub-classification of NHL. FC was used to analyze 650 FNCs of lymphoproliferative processes using a panel of following fluoresceinated antibodies and a three-color Becton Dickinson (San José, CA) FACS scan. When a defined diagnosis of NHL was performed, the combination of cytological features and different expression and co-expression of the antibodies were used to classify, when possible, the specific subtype. Combined FC and FNC provided a diagnosis of benign reactive hyperplasia (BRH) in 286 cases, primary NHL (pNHL) in 148 cases and NHL recurrence (rNHL) in 163 cases, suspicious NHL in 42 cases and inadequate in 11 cases. Clinical control confirmed the diagnoses of rNHL, histological (93 cases) and clinical control (55 cases) confirmed the 148 primary NHL and BRH; 55 cases were lost to the follow-up. In 42 suspicious cases, microscopic features were suggestive of NHL but FC gave unsatisfactory results. Out of 311 cases diagnosed NHL, the evaluation of FC data and the cytological features suggested a specific subtype in 180 cases. All the others, with negative or equivocal phenotype, were diagnosed just NHL not otherwise specifiable. All the FNC/FC diagnoses were confirmed by histology and clinical follow-up except for 55 cases lost to followup. FNC offers vital cells to FC suitable for a timely and accurate diagnosis and sub-classifiction of NHL.