Fine-needle sampling findings in 26 carcinoma ex pleomorphic adenomas: diagnostic pitfalls and clinical considerations.

Preoperative fine-needle samplings (FNS) of 26 histologically proven carcinoma ex pleomorphic adenomas (24 primary tumors and 2 local recurrences in 24 patients) were retrospectively reviewed in order to evaluate their cytologic characteristics. Histologically, 17 were high-grade and 9 were low-grade carcinomas; 10 carcinomas were intratumoral (in situ), and 16 were infiltrative. A cytologic diagnosis of malignancy was established in 13 (50%) cases, 2 (7.7%) were suspicious, and 11 (42.3%) were negative for malignancy (10 pleomorphic adenomas, 1 inflammation). The majority (76.5%) of high-grade carcinomas were correctly diagnosed by FNS, regardless of invasiveness. Paradoxically, most (77.8%) negative results were encountered in low-grade carcinomas. Accurate diagnosis of malignancy on FNS is achieved in high-grade tumors and low sensitivity may cause interpretative difficulties in low-grade tumors. Diagn. Cytopathol. 1999; 21:163-166. Copyright 1999 Wiley-Liss, Inc.