Atlas of Thyroid Cytopathology on Liquid- Based Preparations

Abstract

Fine-needle aspiration (FNA) cytology of the thyroid is the initial diagnostic procedure for the evaluation of nodules and triage thereof to either observation or surgery. Traditionally, thyroid FNAs have been prepared as conventional smears (CS), but these presented certain drawbacks that led to the use of liquid-based preparations (LBP) in thyroid cytology, either as the sole preparation or in combination with CS. Although both methods are useful, the cytomorphologic differences require familiarity for accurate interpretation and avoidance of diagnostic pitfalls. This Atlas was inspired by the increasing use of LBP as a processing method for thyroid FNA. The second edition of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has been widely accepted by pathologists and endorsed by major endocrine clinical organizations including the American Thyroid Association (ATA) for the management of thyroid nodules. It has also received global recognition. This Atlas emphasizes the use of LBP based on TBSRTC diagnostic categories. The Atlas of Thyroid Cytopathology on Liquid-Based Preparations serves as a handy guide to diagnostic cytology on LBP. It is intended to be a ready resource to accurately diagnose thyroid lesions on LBP using key cytomorphologic features. Key cytologic differential diagnosis, gross, and histopathological correlations accompany the cytological findings. The Atlas is lavishly illustrated with color images of various thyroid diseases that should familiarize pathologists with the differences between CS and LBP and between the two commonly used LBPs. The authors have done their best to provide clear, concise, and practical guidance pertaining to cytomorphology and the implications of thyroid FNA diagnoses for patient care in this era of precision medicine.