Sensitivity of fine‐needle aspiration for papillary carcinoma of the thyroid correlates with tumor size

Abstract

Fine-needle aspiration (FNA) of the thyroid for papillary carcinomas is highly sensitive. We sought to determine if the sensitivity of FNA for papillary carcinoma is correlated with the size of the tumor. We reviewed the results of thyroid resections for the last 12 years and correlated the findings with clinical and cytologic information. During the time period, a total of 1,331 resections were performed, and a total of 501 papillary carcinomas were identified, including 291 classic tumors, 65 follicular variants, and 145 “incidental” tumors. Sensitivity for all tumors was strongly correlated with tumor size and ranged from a sensitivity of 0–3% for tumors 2 mm or less, 90% for tumors 1–3 cm (220/244, P < 0.001) and 83% for tumors above 3 cm (47/59, P = 0.02). Abnormal FNAs of classic tumors were always recognized as papillary (262/262) compared to only 49% of follicular variants (32/65, P < 0.001). The sensitivity of FNA for papillary thyroid carcinoma is strongly correlated with tumor size. Tumors smaller than 0.5 cm and tumors larger than 3 cm may be more difficult to successfully aspirate on FNA, and the follicular variant may be more difficult to recognize as papillary. Diagn. Cytopathol., 2011.