title: Diagnostic difficulties associated with phaeochromocytoma--4 case illustrations.
abstract: The diagnosis of phaeochromocytoma can be extremely difficult with 40%-76% of cases escaping diagnosis during life. Until recently, the only available biochemical test for the detection of phaeochromocytoma in Singapore has been the 24-hour urinary vanillyl mandelic acid (VMA). Urinary VMA has been reported to have a high specificity (85%-100%) but variable sensitivity (28%-90%) in the diagnosis of this disease. In 1993, high performance liquid chromatography (HPLC) assays for the measurement of urinary catecholamines and metanephrines were introduced at the Singapore General Hospital. Since 1993, 4 cases of phaeochromocytoma have been detected at our institution. We report here, the diverse clinical presentations of these patients. The urinary-free catecholamine and catecholamine metabolite levels of these patients were compared with corresponding levels from 12 non-phaeochromocytoma patients. Using the reference value of 65.6 mumol/day, we found the urinary VMA to be a highly sensitive (100%) test with a specificity of only 31%. In contrast, a urinary total metanephrine level > or = 9,000 nmol/day was both sensitive (100%) as well as specific (100%).
authors.affiliation: Department of Endocrinology, Singapore General Hospital, Singapore.
authors.forename: K E
authors.initials: KE
authors.lastname: Tan
authors.forename: A C
authors.initials: AC
authors.lastname: Fok
authors.forename: P H
authors.initials: PH
authors.lastname: Eng
authors.forename: D H
authors.initials: DH
authors.lastname: Khoo
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D002395:Catecholamines / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008297:Male; D008676:Metanephrine / Q000652:urine; D008875:Middle Aged; D010673:Pheochromocytoma / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D014642:Vanilmandelic Acid / Q000652:urine
chemical_list: D002395:Catecholamines; D008676:Metanephrine; D014642:Vanilmandelic Acid