Adenoma differential diagnosis

Adrenal adenoma must be differentiated from other adrenal tumors such as , adrenal metastasis, adrenal medullary tumors, and Cushing's syndrome.

Differential Diagnosis	Clinical picture	Imagings	Laboratory tests
Adrenocortical carcinoma	Mass effect symptoms Symptoms related to excess glucocorticoid Symptoms related to excess mineralocorticoid Symptoms related to excess androgen or estrogen secretion	Irregular shape Non-homogeneous density because of central areas of low attenuation due to tumor necrosis Tumor calcification Diameter usually >4 cm Unilateral location High unenhanced CT attenuation values (>20 HU) Non-homogeneous enhancement on CT with intravenous contrast Delay in contrast medium washout (10 minutes after administration of contrast, an absolute contrast medium washout of less than 50 percent) Hypointensity compared with liver on T1 weighted MRI and high to intermediate signal intensity on T2 weighted MRI High standardized uptake value (SUV) on FDG-PET-CT study Evidence of local invasion or metastases	Adrenal androgens (DHEAS) Androstenedione Bioavailable testosterone should be measured in every patient. 17-hydroxyprogesterone Serum estradiol in men and postmenopausal women Cortisol level Fasting serum cortisol at 8 AM following a 1 mg dose of dexamethasone at bedtime
Adrenal adenoma	Symptoms related to excess glucocorticoid Symptoms related to excess mineralocorticoid	Round, homogeneous with sharp margination Unilateral with diameter less than 4 cm Low unenhanced CT attenuation values (<10 HU) Rapid contrast medium washout after administration of contrast An absolute contrast medium washout of more than 50 percent Chemical shift: evidence of lipid on MRI Isointensity with liver on both T1 and T2 weighted MRI sequences	Cortisol level Fasting serum cortisol at 8 AM following a 1 mg dose of dexamethasone at bedtime Renin (PRA) or plasma renin concentration (PRC): very low in patients with primary aldosteronism, usually less than 1 ng/mL per hour for PRA and usually undetectable for PRC
Cushing's syndrome	Rapid weight gain, particularly of the trunk and face with limbs sparing (central obesity) Proximal muscle weakness A round face often referred to as a "moon face" Excess sweating Headache	Imaging may show mass if presents	24-hour urine cortisol Midnight salivary cortisol Low-dose dexamethasone suppression test; high cortisol level after the dexamethasone test is suggestive of hypercortisolism.
Pheochromocytoma	Palpitations especially in epinephrine-producing tumors. Anxiety often resembling that of a panic attack Sweating Headaches occur in 90 % of patients. Paroxysmal attacks of hypertension but some patients have normal blood pressure. It may be asymptomatic and discovered incidentally after screening for MEN patients.	Increased attenuation on non-enhanced CT (>20 HU) Increased mass vascularity Delay in contrast medium washout (10 minutes after administration of contrast, an absolute contrast medium washout of less than 50 percent) High signal intensity on T2 weighted MRI Cystic and hemorrhagic changes Variable size and may be bilateral	Plasma fractionated metanephrines  24-hour urinary fractionated metanephrines
Adrenal metastasis	Symptoms and signs of primary malignancy especially lung cancer General constitutional symptoms: Fever Fatigue Weight loss	Irregular shape and non-homogeneous nature Tendency to be bilateral High un-enhanced CT attenuation values (>20 HU) and enhancement with intravenous contrast on CT Delay in contrast medium washout (10 minutes after administration of contrast, an absolute contrast medium washout of less than 50 percent) Isointensity or slightly less intense than the liver on T1 weighted MRI and high to intermediate signal intensity on T2 weighted MRI (representing an increased water content) Elevated standardized uptake value on FDG-PET scan