Papillary thyroid carcinomas with and without BRAF V600E mutations are morphologically distinct.

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• The BRAF V600E mutation is a frequent genetic alteration in papillary thyroid carcinomas (PTCs).
• This mutation leads to the production of an abnormal BRAF protein.
• Understanding the morphological differences between mutated and non-mutated PTCs is crucial.

Purpose of the Study:

• To identify distinctive morphological features in papillary thyroid carcinomas (PTCs) associated with the BRAF V600E mutation.
• To compare the characteristics of BRAF V600E-positive and negative PTCs.

Main Methods:

• BRAF V600E mutation status was determined using single-strand conformation polymorphism analysis of tumor DNA.
• Morphological features of 34 mutation-positive and 22 mutation-negative PTCs were analyzed.
• Statistical analysis was performed to identify significant associations between mutation status and morphological characteristics.

Main Results:

• BRAF V600E-positive PTCs were more prevalent in older patients (>45 years) and specific variants (classic, tall cell, oncocytic/Warthin-like, subcapsular sclerosing microcarcinomas).
• Follicular and diffuse sclerosing variants were predominantly mutation-negative.
• Mutation-positive tumors exhibited infiltrative growth, stromal fibrosis, psammoma bodies, plump eosinophilic cells, and classic nuclear features; encapsulation was associated with mutation-negative tumors.

Conclusions:

• Papillary thyroid carcinomas with and without the BRAF V600E mutation display significant morphological differences.
• Recognizing these distinct morphological patterns can assist in guiding the selection of appropriate tumors for BRAF V600E genetic testing.