title: A "pheo" lurks: novel approaches for locating occult pheochromocytoma.
abstract: Most, but not all, pheochromocytomas can be localized by computed tomography or magnetic resonance imaging. Here we introduce two novel approaches for localization of pheochromocytoma in a patient in whom conventional imaging modalities failed to show the tumor. First, we establish that measurements of plasma free metanephrines coupled with vena caval sampling are useful for localizing occult pheochromocytoma, particularly when elevations in plasma catecholamines are slight or intermittent. Second, we show that positron emission tomographic scanning using the imaging agent 6-[18F]fluorodopamine as a substrate for the norepinephrine transporter offers a highly effective method for tumor localization. These novel approaches may be of value in difficult cases, where biochemical and clinical evidence of pheochromocytoma is compelling, yet conventional imaging modalities fail to locate the tumor.
authors.affiliation: Pediatric and Reproductive Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1583, USA. karel@mail.nih.gov
authors.forename: K
authors.initials: K
authors.lastname: Pacak
authors.forename: D S
authors.initials: DS
authors.lastname: Goldstein
authors.forename: J L
authors.initials: JL
authors.lastname: Doppman
authors.forename: B L
authors.initials: BL
authors.lastname: Shulkin
authors.forename: R
authors.initials: R
authors.lastname: Udelsman
authors.forename: G
authors.initials: G
authors.lastname: Eisenhofer
mesh_terms: D019797:3-Iodobenzylguanidine; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D000315:Adrenalectomy; D002352:Carrier Proteins / Q000032:analysis; D004298:Dopamine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004837:Epinephrine / Q000097:blood / Q000652:urine; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D009638:Norepinephrine / Q000097:blood / Q000652:urine; D050484:Norepinephrine Plasma Membrane Transport Proteins; D009647:Normetanephrine / Q000097:blood / Q000652:urine; D010673:Pheochromocytoma / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D027981:Symporters; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed; D014682:Vena Cava, Inferior
chemical_list: D002352:Carrier Proteins; D005462:Fluorine Radioisotopes; D050484:Norepinephrine Plasma Membrane Transport Proteins; D019275:Radiopharmaceuticals; C493227:SLC6A2 protein, human; D027981:Symporters; D009647:Normetanephrine; D019797:3-Iodobenzylguanidine; C029253:6-fluorodopamine; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine