Annual increase in the frequency of papillary thyroid carcinoma as diagnosed by fine-needle aspiration at a cytology unit in Sicily.

Objective: An increased frequency of papillary thyroid carcinoma (PTC) has been reported in the literature, including studies based on fine-needle aspiration cytology (FNAC).

Design: To substantiate our own ascertainment of such an increase, we retrieved all the diagnoses of ultrasound-guided FNAC which was performed on 11,389 patients referred for cytological evaluation of a single or dominant thyroid nodule from 1988 to 2010. FNAC yielded 11,258 adequate specimens.

Results: The number of patients with PTC was 200 (age 10-83 yrs) and increased significantly from 1988 to 2010 (r= 0.916, P<0.001). Expressing data as percent of FNAC in any given year, PTC and colloid goiter increased, while adenomatous goiter, follicular lesions and anaplastic or medullary thyroid cancer decreased. PTC accounted for 0% of all FNAC diagnoses in 1988 but for 2% in 2010, with a peak of 2.6% in 2006. Of interest, chronic lymphocytic thyroiditis (CLT) also increased, preceding the increase of PTC by 5-6 years.

Conclusion: We conclude that in the regions on either side of the Strait of Messina (Italy), PTC has become progressively more frequent during the 23-year period between 1988 and 2010 and that this increase lagged behind the increase of CLT.