Papillary thyroid carcinomas with and without BRAF V600E mutations are morphologically distinct
Finkelstein A et al. – BRAF V600E mutation–positive and negative papillary thyroid carcinomas (PTCs) are morphologically different. Recognition of their morphology may help in the selection of appropriate tumours for genetic testing.Methods
- Thirty-four mutation-positive and 22 mutation-negative tumours were identified by single-strand conformation polymorphism of the amplified BRAF V600E region in the tumour DNA.
- Mutation-positive tumours were more common in patients older than 45years (24/33, P=0.05), in classic (23/30, P=0.01), tall cell (4/5) and oncocytic/Warthin-like (2/2) variants of PTC, and in subcapsular sclerosing microcarcinomas (4/4).
- In contrast, all 12 follicular variants (P<0.0001) and two diffuse sclerosing variants were negative for the mutation.
- Mutation-positive tumours displayed infiltrative growth (32/34, P=0.02), stromal fibrosis (33/34, P<0.001), psammoma bodies (17/34, P=0.05), plump eosinophilic tumour cells (22/34, P=0.01), and classic fully developed nuclear features of PTC (33/34, P=0.0001).
- Encapsulation was significantly associated with mutation-negative tumours (15/22, P=0.02).