Diagnosis of lymphoid lesions using cytomorphology and flow cytometry

Flow cytometry (FC) is a useful adjunct to fine-needle aspiration cytology (FNC) in evaluating lymphoproliferative disorders. We present a critical review of 307 lymph nodal and extra lymph nodal lymphoproliferative disorders diagnosed by fine-needle cytology (FNC) and FC. FC was performed over a four years period on 185 palpable and 122 impalpable lymph nodal and extra lymph-nodal lymphoproliferative processes under US or CT control. FC was performed using the following fluoresceinated antibodies: CD3, CD4/8, CD5, CD19/κ/λ, FMC7/CD23/CD19, CD2/3/7, CD38/56/19, bcl-2, CD13/HLA-DR. The series comprised 15 inadequate, 10 suspect and 135 benign reactive hyperplasias (BHR), 70 primary non-Hodgkin lymphomas (NHL) and 77 relapses of NHL (rNHL). FC/FNC diagnoses were controlled by clinical follow-up and/or histology when performed. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the FC/FNC diagnoses of BRH and NHL were calculated as well as of the identification of specific subtypes among the small and medium cell size NHL. Combined FC and FNC diagnoses obtained 93% sensitivity, 100% specificity, 95%%, predictive positive value (PPV) and 63% negative predictive value (NPV) in the diagnosis of BRH and NHL. Specific sub-type was identified in 70/115 cases (61%) of small and medium size NHL with a sensitivity of 63%, specificity of 88%, PPV 95% and NPV 37%. FC applied to FNC enhances the precision of cytological diagnosis in lymph-nodal and extra-lymph-nodal lymphoproliferative disorders and allows sub classification in more than half of the cases, avoiding invasive surgical biopsies in many patients.