BRAF and neurofibromatosis type 1: The pathognomonic clinical and radiological features of OPG, especially in an NF1 context, mean that histological confirmation by biopsy is not usually required/recommended, as it does not affect initial management, although there is international variability in the approach and with the advent of BRAF and MEK inhibitors, even for use in later lines of treatment (e.g. following disease progression after multiple lines of more standard treatments), there has been an increase in the frequency of biopsy for the purpose of obtaining molecular information, especially on BRAF status.