Editing CUA: Adrenal Mass (2011) (section)

== Diagnosis and Evaluation ==

* '''See Figure 1 from Original Guideline'''
** '''Note: figure may contain typographic errors with symbols for APW/RPW''' since Campbell<nowiki>&</nowiki>rsquo;s states: An absolute percent washout (comparing noncontrast values with 15-minute postcontrast density values - ([Enhanced − delayed]/[Enhanced − unenhanced] × 100%) <nowiki>&</nowiki>gt; 60%, or a relative percent washout (RPW) (comparing arterial phase density measurements with 15-minute postcontrast density values - ([Enhanced − delayed]/ Enhanced × 100%)) <nowiki>&</nowiki>gt; 40% on delayed (washout) imaging, is indicative of adenoma
* '''All incidental adrenal masses (excluding myelolipomas, hemorrhages, and cysts) initially require a comprehensive workup, including thorough clinical, radiologic and hormonal evaluations''' to distinguish benign from malignant processes, as well as non-functioning from hyperfunctioning tumours.
* '''History and physical exam'''
** '''Evaluate for overt signs and symptoms of primary adrenal disease; however, most patients with adrenal incidentalomas are asymptomatic'''
* '''Labs'''
** '''Hormonal evaluation'''
*** '''Hypercortisolism is assessed by overnight 1 mg dexamethasone suppression test''' (DST, sensitivity: 85-90 specificity: 95-99). Consideration can be given to using the 24-hour urine free cortisol (UFC, sensitivity: 80-98 specificity: 45-98) for screening with the low dose DST used to differentiate Cushing’s from subclinical Cushing’s syndrome if the cortisol level on the 24-hour test is elevated. A subset of patients with Cushing’s syndrome may have normal UFC (false-negative). For further details on hypercortisolism testing: <nowiki>https://www.ncbi.nlm.nih.gov/pubmed/31069279</nowiki>
*** '''Presence of pheochromocytoma is assessed by 24-hour urine metanephrines and catecholamines'''
**** '''Fractionated plasma metanephrines''' is a newer test that may be more sensitive, but less specific. As such, its use '''should be reserved for confirmatory testing as opposed to primary screening'''. Plasma metanephrine testing may not be widely available outside select centres, therefore 24-hour urinary metanephrines is suggested for initial screening.
*** '''Hypertensive patients with adrenal incidentalomas should be assessed for hyperaldosteronism (HA).'''
**** '''Traditionally, HA has been clinically associated with hypertension and hypokalemia, however, normokalemia occurs in up to 50% of patients with HA.'''
**** '''The best screening test is upright plasma aldosterone concentration to plasma renin ratio (ARR).'''
***** '''Mineralocorticoid receptor blockers (e.g. spironolactone) and some diuretics, particularly potassium sparing diuretics (e.g. amiloride, triamterene) and potassium wasting diuretics (e.g. furosemide, HCTZ, indapamide), should be discontinued at least 4 weeks prior to the ARR'''
***** If ARR results are not diagnostic and hypertension can be controlled with relatively noninterfering antihypertensives, withdrawal of other potentially interfering medications (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, renin inhibitors, dihydropyridine calcium channel antagonists, β-blockers, central α-2 agonists and non-steroidal anti-inflammatory drugs) for at least 2 weeks prior to a repeat ARR is recommended.
***** While acute fluctuations in dietary sodium are reported to not affect the diagnostic accuracy of the ARR, '''patients should be informed to liberalize salt intake leading up to the test to ensure accurate results.'''
*** '''Sex-hormone producing adrenal tumours are rare and typically present with concomitant clinical symptoms (i.e., feminization or virilisation) and therefore systematic screening may not be warranted'''
*** '''Confirmatory hormonal testing is recommended for all positive screening tests to limit false positive results and unnecessary surgeries'''
* '''Imaging'''
** '''Unenhanced CT is initial test to rule in adenoma'''
*** '''Adenomas typically contain a greater proportion of intracellular fat''' in comparison to malignant incidentalomas. Therefore, in CT densitometry, '''a cut-off of <10 HU''' of a region of interest over a mass '''increases the likelihood of adenoma'''
*** Unfortunately, '''lipid-poor adenomas represent up to 30% of all adenomas and may be indistinguishable from malignancy on unenhanced CT'''
*** '''If unenhanced CT is indeterminate, obtain contrast enhanced CT with washouts at 10-15 minutes''' which has excellent sensitivity and specificity in differentiating between adenomas and nonadenomatous incidentalomas
** '''Myelolipoma, cysts and hemorrhages have distinct features on imaging'''
** '''Characteristics of pheochromocytoma and malignant processes include (5):'''
**# '''Size (>3 cm)'''
**# '''Heterogenous texture'''
**# '''Increased vascularity'''
**# '''Attenuation of >10 HU on unenhanced CT'''
**# '''Decreased contrast washout''' at 10 to 15 minutes
** Chemical-shift MRI, like unenhanced CT, uses the lipid-rich property of most adenomas to differentiate benign from malignant. However, '''if an adrenal incidentaloma is indeterminate on unenhanced CT,''' chemical-shift '''MRI may not provide additional information and should be deferred in favour of contrast CT with washouts'''
** '''2-[18F] FDG-PET scan can be useful in detecting metastasis in patients with a history of malignancy''', as metabolically-active lesions typically have increased uptake of FDG versus benign lesions.
** Metaiodobenzylguanidine ('''MIBG) scintiscan can be useful in assessing patients with suspected pheochromocytoma'''
* '''Other'''
** '''Biopsy is currently NOT recommended for the routine workup of adrenal incidentaloma'''. Its findings rarely alter treatment, except in patients with potential metastases or infectious processes. Often, clinical, hormonal and radiologic findings can effectively direct treatment. It is also associated with relatively rare, but significant, complications;  '''pheochromocytoma must always be ruled out before biopsy is undertaken to avoid potentially life-threatening hemorrhage and hypertensive crisis'''