Fine needle aspiration cytology in the management of a parotid mass: a two centre retrospective study

There is a diversity of opinion regarding the role of fine needle aspiration cytology (FNAC) in the pre-operative evaluation of the parotid mass. This study further investigates the role of FNAC from the standpoint of the clinician attempting to resolve one or more clinical issues.

A retrospective study conducted at two UK Hospitals with no overlap of cytopathologists or surgeons. Patients undergoing parotidectomy at each institution were identified from Pathology department databases. The definitive histopathological diagnosis was compared with any pre-operative FNAC diagnosis. Cytology results were classified as suggestive, non-diagnostic, sampling error, or misleading.

The study was conducted in a District General Hospital and a University Teaching Hospital providing secondary care for each community.

For the University Teaching Hospital the sensitivity in distinguishing malignant from benign disease was 79% (95% CI 61-97%) with a specificity 84% (95% CI 73-95%). However, three of eight patients with a primary parotid salivary gland malignancy were reported as having benign disease on FNAC. For the participating District General Hospital the sensitivity in distinguishing malignant from benign disease was 38% (95% CI 13-63%) and specificity 95% (95% CI 73-95%).

Fine needle aspiration cytology does not reliably distinguish a benign from a malignant primary salivary gland neoplasm in the participating institutions. Where clinical teams use FNAC in an attempt to resolve this clinical problem, the results should be interpreted with caution and an ongoing audit of performance is required.