Cytomorphology and immunocytochemistry in the diagnosis of non-Hodgkin lymphomas.

1. Lymph node aspirates from 17 patients with an initial cytologic diagnosis of lymphoma (11 cases) or with suspected lymphoma (6 cases) were studied by immunocytochemistry, which led to a final diagnosis. Immunocytochemical staining demonstrated a B-cell phenotype in 10 cases, one case of anaplastic large cell Ki-1+ lymphoma, one lymphoblastic lymphoma negative for B and T cell markers, one large-cell unclassified lymphoma, and one inconclusive case. Three of the cases with suspected lymphoma were diagnosed as reactive lymphadenitis. 2. Combined cytomorphology and cytochemistry permitted a conclusive diagnosis in 13 out of 14 cases of lymphoma. Histology and immunohistochemistry confirmed the cytologic diagnosis. The inconclusive case was diagnosed as a T pleomorphic, small-cell lymphoma by histology. 3. The accuracy of cytomorphology associated with immunocytochemistry is high. However, the diagnosis of low-grade lymphomas, especially of a T phenotype may be difficult.