P1: SBT
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72 Adrenal Tumors■Catecholamine excess:
➣Basic: 24-h urine for metanephrine, VMA, and free cate-
cholamines
➣Confirmatory: plasma catecholamines, clonidine suppression
test, chromagranin
■Adrenocortical carcinoma: 24-h urine 17-keto-steroids (17-KS), 24-h
UFCImaging
■CT or MRI of abdomen
■MRI: adrenal adenomas, pheochromocytomas hypointense relative
to liver on T2-weighted image; adrenal carcinomas hyperintense on
T2 image
■Nuclear Medicine Studies
➣Fluorodeoxyglucose (FDG) positron emission tomography (PET)
➣Iodine-131-meta-iodobenzylguanidine (MIBG) for suspected
pheochromocytomas
➣19-[131I]iodocholesterol (NP59) scan: functional imaging of adre-
nocortical tissues (labeling compound may be difficult to obtain)differential diagnosis
■Adrenocortical tumors:
➣Hypokalemia from GI losses, diuretic use
➣Cushingoid appearance from exogenous glucocorticoids
➣Cortisol excess in association with depression, stress, alcoholism
(pseudo-Cushing syndrome)
➣Androgen excess from polycystic ovarian syndrome (PCOS), late-
onset congenital adrenal hyperplasia (CAH), androgen ingestion,
oral contraceptives, or progestational agents
■Adrenomedullary tumors: catecholamine excess from anxiety, panic
attacks, illicit drugs/medication withdrawal, hypoglycemia, thyro-
toxicosis
■Metastasis to adrenal
■Bilateral adrenal enlargement:
➣Endocrine: CAH, ACTH excess, hyperaldosteronism due to bilat-
eral adrenal hyperplasia, Cushing syndrome due to bilateral
micronodular or macronodular adrenocortical hyperplasia, Car-
ney’s syndrome
➣Infectious (TB and fungal) and infiltrative disorders (amyloidosis,
hemachromatosis); usually associated with hypoadrenalism
➣Other adrenal tumors: myelolipoma uniformly benign