Fine-Needle Aspiration and Intraoperative Consultation in Thyroid Pathology: When and How?

Abstract

Fine-needle aspiration (FNA) and frozen section evaluation are traditional components of the management of thyroid lesions. Their role and usefulness are dictated by some basic facts about thyroid pathology: (a) nodules are very common; (b) they are benign in the majority of cases; and (c) the diagnosis of malignancy is primarily based on cytologic features in the case of papillary carcinoma, and on the presence of invasion of the tumor capsule or of blood vessels in the case of follicular carcinoma. The common occurrence of benign thyroid nodules mandates a cost-effective effective method for preoperative screening. Since, as already stated, the diagnosis of papillary thyroid carcinoma (by far the most common thyroid malignancy) is based on the identification of characteristic cytologic features, FNA has easily emerged in the past 30 years as the most accurate and cost-effective tool-indeed a true cornerstone-for the preoperative management of thyroid nodules. Standardized terminology to report cytologic diagnoses is highly recommended and is being implemented worldwide. Conversely, the importance of intraoperative frozen section diagnosis has been constantly decreasing over the past years, as a direct consequence of the widespread application of FNA. It may, however, be very useful in cases that are suspicious for papillary carcinoma on FNA and in selected cases with an indeterminate cytologic diagnosis.

Utility of intraoperative frozen sections for thyroid nodules with prior fine needle aspiration cytology diagnosis

“…All these cases were PTC and were confirmed on frozen section and final histology. 26 In conclusion, our study does not support the use of IFS for nodules with prior FNA interpretation of Bethesda II, III, IV, and VI as management was not significantly changed. 1 Frozen section is redundant in these cases and adds to the cost of therapy.…”

“…This has been observed in other studies. 26 In conclusion, our study does not support the use of IFS for nodules with prior FNA interpretation of Bethesda II, III, IV, and VI as management was not significantly changed. IFS is of value for nodules with prior FNA diagnosis of Bethesda I for interpretation of nodule, and Bethesda V for planning surgery.…”

A 4‐MicroRNA signature can discriminate primary lymphomas from anaplastic carcinomas in thyroid cytology smears

“…In this context, fine‐needle aspiration (FNA) plays a worldwide, established role as a valuable and minimally invasive method to achieve a final diagnosis of ATC. Indeed, particularly in elderly patients, FNA can represent the sole adequate pathologic material for diagnosis . The presence of extensive necrosis, inflammation, and atypical nuclei overlapping with other neoplastic conditions, such as metastatic cancers or primary thyroid lymphoma (PTL), can significantly affect the diagnostic potential of FNA in patients with ATC.…”

A High-Resolution Melting Protocol for Rapid and Accurate Differential Diagnosis of Thyroid Nodules

“…Fine-needle aspiration biopsy (FNAB) has emerged over the past 30 years as an accurate and cost-effective procedure for the preoperative screening of thyroid nodules, representing the gold standard for differential diagnosis of benign and malignant nodules. 4 Under recent guidelines, 5,6 cytological smears are classified in five categories for the diagnostic report: Thy 1, nondiagnostic; Thy 2, benign or negative for malignant cells; Thy 3, all follicular lesions (including atypia/ follicular lesion of undetermined significance and follicular neoplasm or suspicious for follicular neoplasm); Thy 4, suspicious; and Thy 5, diagnostic for malignancy.Although the overall accuracy of FNAB is considered excellent, approximately 30% of cytological aspirates do not allow definitive diagnosis of malignancy, because of intrinsic and unavoidable characteristics of samples. 7 The major limitations of FNAB procedures are linked to inadequate and indeterminate specimens and, in that sense, are also linked respectively to the nondiagnostic or follicular lesions categories.…”

“…Fine-needle aspiration biopsy (FNAB) has emerged over the past 30 years as an accurate and cost-effective procedure for the preoperative screening of thyroid nodules, representing the gold standard for differential diagnosis of benign and malignant nodules. 4 Under recent guidelines, 5,6 cytological smears are classified in five categories for the diagnostic report: Thy 1, nondiagnostic; Thy 2, benign or negative for malignant cells; Thy 3, all follicular lesions (including atypia/ follicular lesion of undetermined significance and follicular neoplasm or suspicious for follicular neoplasm); Thy 4, suspicious; and Thy 5, diagnostic for malignancy.…”