Fine-needle aspiration of 154 parotid masses with histologic correlation: ten-year experience at the University of Texas M. D. Anderson Cancer Center

Abstract

Background: Clinical and radiologic assessment of parotid masses cannot distinguish reliably between benign and malignant lesions. The utility of fine-needle aspiration (FNA) of parotid masses at a cancer referral center (where clinicians may be especially adept at diagnosing parotid gland malignancies) remains controversial.

Methods: Between January 1986 and June 1996, 482 parotid glands were resected at the University of Texas, M. D. Anderson Cancer Center (MDACC). A preoperative FNA result was available for 147 of these resections (30%), (corresponding to 154 preoperative FNAs). The results of 154 consecutive preoperative FNAs were compared with the corresponding histopathologic diagnoses.

Results: Histologic evaluation revealed 76 malignant tumors and 78 benign lesions (67 neoplastic and 11 nonneoplastic). The FNA smear was nondiagnostic in two benign and two malignant cases. The cytologic diagnosis was true-positive in 61 cases (82% sensitivity), and true-negative in 65 cases (86% specificity). There were 11 false-positive results. Eight of these cases were classified as false-positive because they were suspicious for malignancy; five of the eight were outside cases. In addition, there were 13 false-negative results (6 metastatic lesions, 3 low grade mucoepidermoid carcinomas, 2 acinic cell carcinomas, and 2 carcinoma ex pleomorphic adenomas) (9%). Fifty-one of the malignant lesions (84%) and 60 of the benign lesions (92%), including 93% of the benign tumors, were classified accurately. Ten of ten lymphoma cases in this series were identified correctly.

Conclusions: FNA of parotid masses at a major referral cancer center has a sensitivity of 82%, a specificity of 86%, and an overall diagnostic accuracy of 84%. FNA plays an important role in the preoperative and postoperative assessment of parotid masses by aiding in the evaluation of tumors in poor surgical candidates and unresectable tumors, and by identifying metastases from other sites, reticuloendothelial tumors, and nonneoplastic inflammatory conditions.