One case not meeting criteria for NIFTP maintained the diagnosis of encapsulated FVPTC without invasion but demonstrated significant mitotic activity (three mitoses/ten HPF) and lacked lymph node metastases and BRAF V600E mutation.
This study correlates histological features, immunoreactivity for CK19, HBME, and Gal, and BRAF V600E mutation with lymph node (LN) metastasis and follow-up in FVPTC.
BRAF mutations were only detected in FVPTC (10%); the BRAF mutations in these cases (K601E and G474R) are different from the typical BRAF(V600E) mutation of conventional PTCs.