Thyroid cytology: practical tricks and pitfalls

Area of Science:

• Endocrinology
• Cytopathology
• Oncology

Background:

• Thyroid nodules are highly prevalent, detected in over 50% of adults, often incidentally via ultrasonography.
• While most thyroid nodules are benign (70%), a significant portion (20%) are indeterminate, requiring careful evaluation.
• The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) classifies indeterminate lesions into subgroups like atypia of undetermined significance (AUS), follicular neoplasm (FN), and suspicious for malignancy (SFM).

Purpose of the Study:

• To review and discuss potential diagnostic pitfalls in the cytologic evaluation of thyroid lesions.
• To address challenges in classifying indeterminate thyroid nodules using fine-needle aspiration cytology (FNAC).
• To enhance the accuracy of thyroid nodule diagnosis and reduce false positive/negative results.

Main Methods:

• Literature review of studies on thyroid nodule cytopathology.
• Analysis of diagnostic accuracy and limitations of FNAC for thyroid lesions.
• Discussion of morphological features contributing to diagnostic errors in thyroid FNAC.

Main Results:

• Fine-needle aspiration cytology (FNAC) for thyroid nodules has high accuracy but is susceptible to diagnostic pitfalls.
• Overlapping cellular and background morphological features can lead to misinterpretation of thyroid cytology.
• These pitfalls can result in false positive or false negative diagnoses, impacting patient management.

Conclusions:

• Accurate cytologic evaluation of thyroid lesions is crucial for appropriate patient management.
• Awareness of potential pitfalls in FNAC interpretation is essential for cytopathologists.
• Further refinement in diagnostic criteria and techniques may improve the accuracy of indeterminate thyroid nodule classification.