A prospective assessment defining the limitations of thyroid nodule pathologic evaluation

Area of Science:

• Endocrinology
• Pathology
• Oncology

Background:

• Clinical management of thyroid neoplasms relies on light microscopy, but its diagnostic accuracy and precision are not well-defined.
• Variability in diagnosis can affect patient treatment and outcomes.

Purpose of the Study:

• To assess the inter- and intraobserver variability in preoperative cytopathologic and postoperative histopathologic diagnoses of thyroid nodules.
• To evaluate the consistency of diagnoses made by local and central pathologists and cytopathologists.

Main Methods:

• A prospective, multicenter trial involving 653 patients with 776 surgically resected thyroid nodules (≥1 cm).
• Histopathology slides were reviewed by central histopathologists, and cytopathology diagnoses were compared against a central panel of cytopathologists.
• Inter- and intraobserver concordance rates were calculated for both diagnostic methods.

Main Results:

• Histopathologic distinction between benign and malignant diagnoses showed high concordance (90-91%).
• Concordance for cytopathologic diagnoses using the Bethesda System was lower (64.0% interobserver, 74.7% intraobserver).
• Central cytopathologists produced fewer indeterminate diagnoses compared to local pathologists (41.2% vs. 55.0%).

Conclusions:

• Significant inter- and intraobserver variability exists in the cytopathologic and histopathologic evaluation of thyroid nodules.
• This variability underscores inherent limitations in relying solely on visual microscopic diagnosis.
• Standardization of diagnostic criteria, such as the Bethesda System, is crucial for improving consistency.