HYU Onc - Adrenal Flashcards
Adrenal in relation to Gerota’s
Located within a compartment of Gerota’s fascia
Arterial supply to adrenal
3 arteries
inferior phrenic –> superior adrenal artery
aorta at SMA –> middle adrenal artery
renal artery –> inferior adrenal artery
Venous supply to adrenal on right
right adrenal = ‘vein of death’
comes from IVC and/or right renal vein
Venous supply to adrenal on left
comes from left renal vein +/- inferior phrenic vein
Ddx benign adrenal mass
Adrenal adenoma (~15% metabolically active –> cortisol and/or aldosterone production)
Pheo (90% benign)
Myelolipoma
Oncocytoma
Ganglioneuroma
Cyst
Hemorrhage
Ddx malignant adrenal mass
ACC
Met lesion
Staging of ACC
T1: <5 cm, confined to adrenal
T2: > or = 5cm or functional sympathetic paraganglioma, confined to adrenal
T3: Local invasion into surrounding tissues
Stage I: T1N0M0
Stage II: T2N0M0
Stage III: T3N0M0, T1-3N1M0
Stage IV: M1 disease
Radiographic assessment of adrenal mass
- Noncon CT?
- Best studies and parameters?
Assess intracytoplasmic lipid content: high lipid is associated with low attenuation (<10 HU) on noncon CT
- On MRI, associated with opposed phase chemical shift
- These are both diagnostic for adrenal adenoma
~30% of adenomas are lipid poor and don’t exhibit <10 HU on CT or signal drop out on MRI –> Get CT Washout Imaging
Washout parameters for adrenal adenoma vs cancer
- CT?
- MRI?
> 60% absolute washout
40% relative washout
- These are both highly specific for adrenal adenoma
Cancer is greedy and retains contrast, so it won’t wash out
MRI drop out indicates presence of fat and therefore a benign mass
Myelolipoma HU/appearance on imaging (CT and MRI)
Macroscopic lipid of -10 to -20 HU on noncon CT is diagnostic
Benign, 90% metabolically silent
High T1 signal on MRI
***On MRI, fat is bright on T1 and H20 is bright on T2
ACC appearance on imaging
Mean enhancement on noncon CT is 39 HU
Generally >4cm masses with heterogeneous appearance, calcifications, necrosis
Pheo appearance on imaging
> 10 HU on unenhanced CT
Enhance to >100 HU with contrast
Well circumscribed, light-bulb sign on T2 MRI
(ACC and metastatic lesions can also be bright on T2)
Relative adrenal mass resection indications
Metabolic activity or concern for malignancy (~20% of incidentalomas)
>4 cm mass in young, healthy patients
>6 cm mass and NOT myelolipoma in all surgical candidates (1/3rd of these will be malignant)
General metabolic evaluation for adrenal masses
Test Cortisol and Catecholamine for All, Aldosterone and Sex Steroids for some
Cortisol Testing
- Most common - what is positive/negative and why?
- Alternatives
Low dose dexamethasone suppression test (corticosteroid)
- 1 mg dexamethasone at 11 PM (OCPs cause FPs) given to suppress ACTH secretion from the anterior pituitary
- If 8 AM serum cortisol is <5 mcg/dL, it rules out an ACTH-independent glucocorticoid secretion by an adrenal nodule (which would not respond to ACTH suppression)
- AKA test is positive if cortisol remains HIGH despite dex SUPPRESSION
-* Don’t perform if pheo suspected (>10 HU on imaging) as this can trigger catecholaminergic crisis
Alternatives:
- Late night (11pm) salivary cortisol (if testing is normal, you know ACTH hyperproduction is not etiology)
- 24-hour urinary cortisol (obtain 2 or more collections to reduce risk of FN)
What is next testing once hypercortisolemia is identified?
Get late-afternoon serum ACTH to determine if the process is ACTH dependent (>10 pg/mL) or independent (<5pg/mL)
Catecholamine Testing
Pheo screening
- Performed with plasma-free metanephrines (preferred)
–> Can be drawn at same time as AM cortisol
–> No caffeine for 24 hours
–> FPs can be caused by TCAs, MAOIs, SSRIs, tylenol
–> draw in supine position after patient has been resting for 20 minutes
–> positive result is 4x normal value
- Can also use 24-hour total urinary fractionated metanephrines
*24 hour urine tests require normal renal function to be worthwhile
Pheo rule of 10s
Roughly 10% (each) of pheos are:
- Normotensive
- Bilateral
- Familial
- Malignant
- Pediatric
- Extra-adrenal
- Multiple
Aldosterone Testing
- When test for this?
- What are we testing for?
- What is a positive screening test?
If a patient has HTN and hypoK, correct hypoK and stop potentially interfering medications (spironolactone, eplerenone) for 6 weeks
- Screen for primary hyperaldosteronism (Conn’s syndrome) with morning/sitting plasma aldosterone (>15 ng/mL is a positive test) and renin levels (aldosterone to renin ratio (ARR) >20-30 is a positive test)
If aldosterone screening test is positive?
Confirm Conn’s with 24 hour urine study with salt loading
- Urine sodium >14 mcg and urine K+ >30 mEq/24 hour are positive tests
- Can also do fludrocortisone suppression or captopril challenge
If confirmatory test is positive, get AVS (could have bilateral lesions even in setting of unilateral adenoma)
A functional adenoma is treated with adrenalectomy, but bilateral adrenal hyperplasia is treated with an aldosterone receptor antagonist like spironolactone or eplerenone
When do you do Sex Steroid Testing?
If there is a strong suspicion for ACCn (stigmata of feminization or virilization), can test for sex steroids to use as a form of surveillance after resection
(DHEA, 17-OH progesterone, androstenedione, testosterona, 17B-estradiol)
Adrenal mass follow-up?
All adrenal masses should have at least 2 years follow-up imaging (CT at 6, 12, 24 months)
Metabolically silent adrenal masses:
< 3 cm –> no metabolic follow-up needed
> 3 cm –> 20% can have hormonal hypersecretion at follow-up –> annual metabolic evaluation for 4 years