CONTEXT: Pheochromocytomas and paragangliomas (PPGLs) are diagnosed earlier in patients with hereditary than sporadic disease. Whether other factors influence age at diagnosis is unclear. OBJECTIVE: We examined ages at which PPGLs were diagnosed according to different catecholamine phenotypes and locations of tumors. DESIGN & SETTING: Retrospective multicenter study. PATIENTS: Patients with PPGLs included 172 with and 183 without identified germline mutations or hereditary syndromes. BIOCHEMICAL MEASUREMENTS: Differences in plasma concentrations of metanephrine, a metabolite of epinephrine, were used to distinguish epinephrine-producing tumors from those lacking epinephrine production. RESULTS: Patients with epinephrine-producing tumors were diagnosed 11 yr later (P