Diagnostic assessment of enlarged superficial lymph nodes by fine needle aspiration.

Two hundred eighty-five consecutive outpatients with enlarged superficial lymph node either clinically suspicious (152) or with a previous diagnosis of a malignant tumor (133) underwent fine needle aspiration (FNA) followed by excisional biopsy. Cytologic and/or cytologic-immunophenotypic diagnoses made on direct smears were compared with subsequent histologic findings. The comparison demonstrated (1) a high rate of conclusive cytologic diagnoses in the assessment of metastatic malignancies, with an overall accuracy rate of 99.1% and a typing accuracy rate of 96.5%; (2) a high rate of conclusive diagnoses in the assessment of high grade non-Hodgkin's lymphomas and Hodgkin's disease, with the exception of the lymphocytic predominance variant of the latter; and (3) significant limitations in the assessment of low grade non-Hodgkin's lymphomas because of the high rate of false-negative diagnoses in cases with a substantial nonmalignant cell component. This was particularly evident in follicular centroblastic-centrocytic lymphomas. Immunocytochemistry appeared to be of limited value in the distinction between centroblastic-centrocytic follicular lymphomas and reactive follicular hyperplasia. The results confirmed the diagnostic value of fine needle aspiration as the first step in the workup of patients with nodal enlargement suspicious for malignancy. In the area of low grade non-Hodgkin's lymphomas, morphologic and immunocytochemical methods need to be supplemented by molecular techniques in order to achieve conclusive diagnoses.