The Italian Consensus for the Classification and Reporting of Thyroid Cytology: Cytohistologic and molecular correlations on 37,371 nodules from a single institution

Abstract

BACKGROUND:The Italian Consensus for the Classification and Reporting of Thyroid Cytology (ICCRTC) includes six diagnostic categories (TIR 1/1C, TIR 2, TIR 3A, TIR 3B, TIR 4, and TIR 5), each indicating a different risk of malignancy. The objective of this monocentric retrospective study was to evaluate the distribution of the ICCRTC classes at the authors' institution and assess their cytohistologic correlations. METHODS: The authors retrospectively collected 37,371 consecutive cytologic reports of thyroid nodules and described the clinical-pathologic features of the different cytologic categories. The cytologic diagnoses also were compared with histologic outcomes in a subset of patients. RESULTS: The cytologic classes were distributed as follows: nondiagnostic, 15.6%; benign, 66.5%; low-risk indeterminate, 10% (TIR 3A); high-risk indeterminate, 3.5% (TIR 3B); suspicious, 1.7%; and malignant, 2.6%. According to histology, the risk of malignancy was very high in the nondiagnostic category (29.8%), with young male patients more exposed to malignancy, and it was relatively high among benign (7.8%) and indeterminate nodules (32.5% in TIR 3A; 52.1% in TIR 3B), mainly because of the high prevalence of follicular architecture in malignant tumors. On histology, the malignancy rates were 92.4% and 99.3% for the suspicious and malignant categories, respectively; aggressive variants of papillary thyroid carcinoma were mostly diagnosed in these categories. CONCLUSIONS: In this series, nondiagnostic nodules showed high prevalence and, surprisingly, high malignancy rates. Malignant tumors with follicular architecture represented a diagnostic pitfall in benign and indeterminate nodules. The suspicious and malignant categories had high specificity for malignancy. Importantly, the ICCRTC had high reliability for identifying preoperatively aggressive histotypes of thyroid carcinoma.. Cancer Cytopathol 2022;.

MicroRNA expression profiling of RAS-mutant thyroid tumors with follicular architecture: microRNA signatures to discriminate benign from malignant lesions

“…NRAS , KRAS and HRAS are oncogenes: their activating mutations are known to promote cell growth and proliferation. However, if detected preoperatively on thyroid nodules, RAS mutations show a suboptimal positive predictive value for malignancy [ 21 ]. Therefore, in this study we investigated miRNA expression profiles in benign and malignant RAS -mutant thyroid neoplasms with the aim of identifying miRNAs that could serve as diagnostic markers in presurgical setting, specifically in RAS -mutant thyroid nodules, thus helping refine their risk of malignancy.…”

Indeterminate Thyroid Nodules: From Cytology to Molecular Testing

“…Most NIFTPs are cytologically classified as indeterminate nodules, and only a small part is included among the suspicious and malignant categories. They are not considered benign nor malignant tumors, but a separate histological category [ 15 ]. In the new WHO classification of tumors of endocrine organs, NIFTPs are placed in the category of “low-risk neoplasms” [ 16 ].…”

Unveiling Variations: A Comprehensive Comparison of Five Globally Used Thyroid Cytology Reporting Systems With Histopathological Correlation

“…Subsequent to this, the Japanese Reporting System for Thyroid Aspiration Cytology (JRSTAC) was introduced in 2005, offering a more structured framework, which was subsequently refined into the currently adhered JRSTAC 2019 reporting system [ 6 ]. This evolution has been mirrored globally with different countries adopting their own reporting guidelines, including the Italian Consensus for the Classification and Reporting of Thyroid Cytology (ICCRTC 2016) [ 7 ], the UK Royal College of Pathologists System for Reporting Thyroid Cytopathology (UK RCPath 2016) [ 8 ], the Royal College of Pathologists of Australasia and Australian Society of Cytology (RCPA/ASC 2019) classification system [ 9 ], and The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC 2023) [ 10 ].…”