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

Preoperative fine-needle samplings (FNS) of 26 histologically proven carcin oma ex pleomorphic adenomas (24 primary tumors and 2 local recurrences in 2 4 patients) were retrospectively reviewed in order to evaluate their cytolo gic characteristics. Histologically, 17 were high-grade and 9 were low-grad e carcinomas; 10 carcinomas were intratumor al (in situ), and 16 were infil trative. 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 pleom orphic adenomas, 1 inflammation). The majority (76.5%) of high-grade carcin omas were correctly diagnosed by FNS, regardless of invasiveness. Paradoxic ally, most (77.8%) negative results were encountered in low-grade carcinoma s. Accurate diagnosis of malignancy on FNS is achieved in high-grade tumors an d low sensitivity may cause interpretative difficulties in low-grade tumors . Diagn. Cytopathol. 1999; 21:163-166. (C) 1999 Wiley-Liss, Inc.