Diagnosis and subclassification of primary and recurrent lymphoma. The usefulness and limitations of combined fine-needle aspiration cytomorphology and flow cytometry.

The primary diagnosis of non-Hodgkin lymphoma/leukemia by fine-needle aspiration (FNA) is still controversial and relatively underused. We evaluated our FNA experience with lymphomas using the revised European-American classification of lymphoid neoplasms to determine the reliability of FNA when combined with flow cytometry in the diagnosis of lymphoma, the types of diagnoses made, and the limitations of this technique. Slides and reports from all lymph node and extranodal FNAs performed during the period January 1, 1993, to December 31, 1998, with a diagnosis of lymphoma or benign lymphoid process were reviewed. There were 290 aspirates from 275 patients. These included 158 cases of lymphoma, of which 86 (54.4%) were primary and 72 (45.6%) were recurrent. There were 44 aspirates suggestive of lymphoma and 81 benign/reactive diagnoses. With diagnoses suggestive of lymphoma considered as positive for lymphoma, levels of diagnostic sensitivity and specificity were 95% and 85%, respectively. Specificity was 100% when only definitive diagnoses of lymphoma were considered. Clearly, FNA and immunophenotyping by flow cytometry are complementary and obviate a more invasive open biopsy for many patients with lymphadenopathy.