Fine-needle aspirates of thyroid microcarcinoma

Area of Science:

• Endocrinology
• Surgical Pathology
• Cytopathology

Background:

• Ultrasound advancements enable detection of smaller thyroid nodules.
• Fine-needle aspiration (FNA) is crucial for preoperative evaluation of thyroid nodules.
• Distinguishing incidental from non-incidental microcarcinoma poses clinical management challenges.

Purpose of the Study:

• To analyze the cytologic characteristics of incidental versus non-incidental thyroid microcarcinoma.
• To correlate preoperative FNA diagnoses with histopathology findings.
• To assess the frequency of indeterminate diagnoses in incidental microcarcinoma.

Main Methods:

• Retrospective analysis of thyroid FNAs from 2010-2014.
• Categorization of aspirates using the Bethesda System for Reporting Thyroid Cytopathology.
• Correlation of cytologic diagnoses with surgical histopathology and nodule size stratification.

Main Results:

• 259 malignancies were identified from 587 correlated FNAs.
• Incidental microcarcinoma (≤0.5 cm) comprised 48% of microcarcinomas.
• Indeterminate FNA diagnoses (FLUS, FN, SM) were significantly higher for incidental (60%) versus non-incidental (27%) microcarcinoma.

Conclusions:

• Incidental microcarcinoma is a common finding, representing 21% of malignant thyroidectomy nodules.
• Preoperative FNA for incidental microcarcinoma has a higher rate of indeterminate diagnoses.
• These findings highlight the need for careful management of incidental microcarcinoma detected via FNA.