A prospective comparison of fine-needle aspiration cytology and histopathology in the diagnosis and classification of lymphomas.

INTRODUCTION Surgical biopsy examination is the gold standard for lymphoma diagnostics. However, fine-needle aspiration cytology (FNAC) offers several advantages in that it is quick, inexpensive, and the aspiration procedure has very few complications. This prospective study compares the diagnostic outcome between FNAC and surgical biopsy. MATERIALS AND METHODS A total of 103 patients (>15 years) with lymphadenopathy and accessible lymph nodes underwent both diagnostic procedures. Immunophenotyping was performed on both FNAC and histopathological specimens. The updated KIEL classification was used for primary diagnosis and the WHO classification for reclassification. RESULTS FNAC- and histopathology-based diagnoses were concordant in 76 patients. In 10 patients, there was a major diagnostic discordance: four differed with regard to degree of malignancy (low- versus high-grade NHL), three lymphoma versus reactive changes, and three regarding Hodgkin's lymphoma versus anaplastic large cell lymphoma. In 10 patients there was some (minor) discordance regarding subclassification: in eight patients the results of immunophenotyping differed, in two cases there were discrepancies in the cell type classification. In the remaining seven cases, there were diagnostic difficulties due to an insufficient sample. two serious adverse events occurred following surgical biopsy. CONCLUSIONS FNAC is an accurate method in the diagnosis of lymphomas when the cytologic diagnosis is corroborated by immunophenotyping. However, an increasing use of FNAC for primary diagnosis and classification of lymphomas may result in a loss of archival tissue for complementary analyses, reclassification, and research purposes. In addition, some of the lymphoma entities are impossible to diagnose with use of the FNAC technique.