SDHB and neoplasm: Of note, SDHA-related metastatic PHEO/PGLs were found to have similarities with SDHB-related metastatic PHEO/PGL in terms of their tendency to have the primary tumor occur in extra-adrenal locations, site of metastases, exhibition of a noradrenergic/dopaminergic biochemical phenotype, avidity for 68Ga-DOTATATE on PET/CT, low 123I-MIBG avidity, and highly aggressive disease and poor treatment response (17, 41–43, 45, 46, 57–61).