Dendritic reticulum cells and immunophenotype in aspiration biopsies of lymph nodes. Value in the subclassification of non-Hodgkin's lymphomas.

Twenty-seven lymph node aspirates were identified for which histologic confirmation of non-Hodgkin's lymphoma was subsequently obtained. Fifteen aspirates interpreted as reactive hyperplasia were also examined. All aspirates were studied by immunoperoxidase on cytospin preparations with the use of antibodies DRC1, kappa, lambda, CD3, CD5, and CD20. The follicular lymphomas could not be identified reliably by morphologic examination of aspirate smears. Clusters of DRC1-positive (DRC1+) cells were present in seven of seven follicular lymphomas, one of one mantle zone lymphoma, and one of seven small lymphocytic lymphomas. Rare DRC1+ cells were present in one of one diffuse mixed and one of seven large cell lymphomas. One lymphoblastic, one Burkitt's, and two diffuse small cleaved cell lymphomas had no DRC1+ cells. None of the seven follicular lymphomas was CD5 positive (CD5+), whereas five of the seven small lymphocytic lymphomas were CD5+. Conversely, all seven follicular lymphomas were CD20-positive (CD20+), but only one of seven small lymphocytic lymphomas was CD20+. Nineteen of the lymphomas, including all 7 of the follicular lymphomas, were either kappa or lambda positive. The other eight lymphomas were T-cell (1), B-cell (1), true histiocytic (1), or "null" cell (5). The reactive aspirates had both kappa- and lambda-positive B-cells. Seven of the 15 had clusters of DRC1+ cells. To further evaluate these antibodies, the authors studied 29 additional, surgically biopsied, non-Hodgkin's lymphomas that had not been aspirated. Similar results were obtained, except that three of five diffuse small cleaved cell lymphomas had DRC1+ cells. DRC1, in conjunction with antibodies to CD5, CD20, kappa, and lambda, helps to distinguish follicular lymphoma from small lymphocytic lymphoma. DRC1 is not useful in separating reactive hyperplasia from follicular lymphoma.