[The utility of aspiration cytology for the distinction of aggressive and non-aggressive papillary carcinoma of the thyroid].

Preoperative identification of the aggressive variants of papillary thyroid carcinoma (PTC) by fine needle aspiration (FNAC) has been suggested and different systems for distinguishing them from classical variant of PTC have been employed, including a point-based cytology grading system as suggested by Damiani et al., that we currently use in our Institution. The aim of this paper is to verify if distinction of PTC in aggressive or nonaggressive variants impacts on surgical treatment. In 7 years, from 1998 to 2005, 13586 cases of FNAC of thyroid have been performed; among them 156 PTC. The cytological material of thirty complete thyroidectomies with histology proven papillary thyroid carcinoma were reviewed. 11/30 cases were correctly stratified into the appropriate low or high-grade category. The cytological grading system was discordant with the final histopathological diagnosis in 9/30 cases while in 10 cases the grade was not assessed. Eight cases were downgraded and therefore the low grade papillary carcinoma diagnosed at cytological level turned to be high grade at histology. When those cases were reviewed, the histology of seven cases diagnosed as tall cell variant of PTC failed to show a percentage of tumour cells higher than 50% and therefore it would be better to diagnose them as classical variant of PTC. One case was under-graded at FNAC. The case that was cytologically upgraded was a follicular variant of PTC in Hashimoto thyroiditis with a focus of tall cells. All patients underwent thyroidectomy or thyroidectomy plus lymphadenectomy and from our results the pre-operative diagnosis did not effect the surgical treatment. No patient died of the disease.