VHL and paraganglioma: Tumors that originate from the adrenal medulla are defined as PCCs, which are thought to be caused by the mutation of RET, VHL, MAX, NF1, and TMEM127; while tumors located in extra-adrenal positions are called paragangliomas, which were more likely to be caused by the mutation of SDHx, MDH2, and HIF2A (54).