Italian consensus for the classification and reporting of thyroid cytology.

Abstract

IntroductionThyroid nodules are diagnosed with increasing frequencyin clinical practice. The first step in the management ofpatients presenting with thyroid nodules is an accuratetriage of those who should be referred to surgery [1–5]. Inspite of the advances in ultrasound (US) imaging [6–8] andthe promising results of molecular analysis [9–16], thisbasic step still strongly relies on cytology [3]. Among theacronyms used to indicate the sampling technique forthyroid cytology (FNA, FNAB, FNAC, FNC), fine-needleaspiration (FNA) is the most frequently adopted and it willbe employed in this document. When the cytologicspecimen is obtained without aspiration the term FNC(fine-needle cytology) may be used [2].In the recent years, a variety of four- to six-tieredreporting schemes for thyroid cytology have been proposedby different societies and institutions, with the aim ofimproving the communication between cytopathologistsand clinicians [17].With the aim to standardize the diagnostic terminologyin thyroid FNA, in 2007 the United States National CancerInstitute (NCI) has proposed a reporting system for thyroidcytology based on the NCI Thyroid FNA State-Of-ScienceConsensus Conference [18]. This system has gained widediffusion and the atlas ‘‘The Bethesda System for Report-ing Thyroid Cytology’’ (BSRTC) provided well-definedcriteria with exhaustive explanatory notes [19]. Followingthe recommendations of the 2009 European Federation ofCytology Societies (EFCS) symposium aiming at theworldwide unification of the reporting systems for thyroidcytology [20], a working group of the Royal College ofPathologists (RCPath) updated the reporting systemalready in use in UK since 2007 [21] using criteria that aresimilar to those used in BSRTC [22].In Italy, a 5-tiered classification, proposed in 2007 bythe Italian Society for Anatomic Pathology and Cytologyjoint with the Italian Division of the International Academyof Pathology (SIAPEC-IAP) [2], is currently used by mostinstitutions. In 2012 the Italian Societies of Endocrinology,i.e., the Italian Thyroid Association (AIT), the ItalianAssociation of Clinical Endocrinologists (AME), the Ital-ian Society of Endocrinology (SIE) and the SIAPEC-IAPappointed a working panel of experts to update the formerconsensus in line with the indications of the EFCS. Thepresent document provides a reporting scheme for thyroidcytology and the suggested clinical actions. This Consen-sus is not meant to address in detail all the morphological