Investigation of lymphoid lesions of the Head and Neck using combined fine needle aspiration cytology and flow cytometry: accuracy and pitfalls.

OBJECTIVE: We reviewed the diagnostic utility of combined fine needle aspiration cytology (FNAC) and flow cytometry (FC) in the diagnosis of lymphoid lesions of the head and neck.

METHOD: 1402 patients with combined FNAC-FC reports were correlated with follow-up information. Rapid on-site evaluation (ROSE) of cytological specimens was performed in 52% of cases.

RESULTS: 211 lymphoid malignancies were identified, including 198 non-Hodgkin lymphoma (NHL) and 13 Hodgkin lymphoma (HL). Accuracy measures for NHL were: sensitivity 95.5%; specificity 99.9%; PPV 99.5%; NPV 99.2%; accuracy 99.3%. Only 7/13 cases of HL were detected by FNAC-FC. False negative cases included HL (6 cases), diffuse large B-cell lymphoma (4), T-cell lymphoma (2), follicular lymphoma (1), marginal zone cell lymphoma (1) and B-cell non-Hodgkin lymphoma, not otherwise specified (1). Two false positive results were identified: one immunoblastic hyperplasia reported as suspicious for HL and one case reported as suggestive of NHL that was found to be reactive hyperplasia. Cases collected with ROSE had a significantly lower rate (p < 0.0001) of insufficient cells for FC analysis (7.0%) than cases where ROSE was not performed (16.4%). Sensitivity (p < 0.0001) and NPV (p = 0.0023) were significantly higher for ROSE-collected specimens. None of the FN NHL cases had ROSE performed.

CONCLUSIONS: FNAC-FC is a highly sensitive and specific test for NHL. Diagnostic errors mostly involved HL, large cell lymphomas and T-cell lymphomas. ROSE results in a significantly higher adequacy rate for FC and higher sensitivity for NHL. This article is protected by copyright. All rights reserved.