Published in:
01-04-2014 | Original Article
Morphology predicts BRAF
V600E mutation in papillary thyroid carcinoma: an interobserver reproducibility study
Authors:
Renu K. Virk, Constantine G. A. Theoharis, Avinash Prasad, David Chhieng, Manju L. Prasad
Published in:
Virchows Archiv
|
Issue 4/2014
Login to get access
Abstract
Papillary thyroid carcinomas (PTC) with BRAF
V600E mutation are morphologically distinctive. They are typically classic or tall cell variants, show infiltrative borders, and are associated with desmoplasia/fibrosis, psammoma bodies, and well-developed nuclear features of papillary carcinoma. We hypothesize that morphologic features of PTC can help in the prediction of BRAF
V600E mutation, and we evaluate the accuracy and the interobserver reproducibility of such prediction. Hematoxylin and eosin-stained sections from 50 PTCs comprising of 26 mutation-positive and 24 mutation-negative tumors were examined. BRAF
V600E mutation was predicted correctly in 42/50 tumors (accuracy, 84 %) with 96 % sensitivity, 71 % specificity, and 78 % positive and 94 % negative predictive values (NPV). Subtle nuclear features of PTC (n = 10) had the highest (100 %) negative predictive value followed by well-circumscribed non-infiltrative tumor borders (17/22 mutation-negative tumors, 95 % NPV). The positive predictive value of infiltrative tumor borders (21/28 [75 %] mutation-positive), desmoplasia/fibrosis (23/31 [74 %] mutation-positive), and psammoma bodies (13/20 [65 %] mutation-positive) increased to 100 % when all three features were present (n = 8/8 mutation-positive). To assess interobserver reproducibility, two pathologists blinded to the mutational status evaluated 30 PTCs (15 mutation-positive and 15 mutation-negative) after self-training on 10 PTCs with known BRAF
V600E mutational status (five mutation-positive and five mutation-negative). The prediction of the mutation was achieved with substantial agreement (κ value, 0.79) and accuracy (25/30, 83 %). This study demonstrates that BRAF
V600E mutation in papillary thyroid carcinoma can be predicted on morphology with accuracy and with substantial interobserver agreement.