These studies either confirmed or first showed that SDHB-related PHEOs/PGLs are most commonly extra-adrenal and larger at first presentation, with a characteristic noradrenergic and/or dopaminergic biochemical phenotype, as well as much lower catecholamine tumor concentrations than any other sporadic or hereditary PHEOs/PGLs. The gene discussed is SDHB; the disease is neoplasm.