adrenalmass.org - helpful workup/management algorithms

Adrenal incidentaloma

• = mass > 1 cm found incidentally on imaging
• Important questions
  • Functional? (~15% of adrenal adenomas are metabolically active)
    • 12% cortisol, 5% pheo, 2% aldosterone
    • Aldosteronoma = Conn's syndrome
    • Cortisol-secreting = Cushing's syndrome
    • Resect metabolically active masses
  • Malignant? History of malignancy? (Metastases to adrenal more common than primary ACC)
    • > 4 cm solid mass = higher risk of being malignant
    • > 4 cm - resect in young/healthy patients
    • > 6 cm - 1/3 are malignant; resict in all surgical candidates (unless obviously myelolipoma (benign))
• Benign - adenoma (can secrete cortisol or aldosterone), pheochromocytoma, myelolipoma, oncocytoma, epithelial cyst
• Malignant - metastasis; adrenal cortical carcinoma

Adrenal layers (superficial to deep)

• Embryology
  • Adrenal cortex develops from mesoderm
  • Adrenal medulla develops from ectoderm
  • **hide**Rarely can see adrenal rest in testis - benign
  • **hide**Neonatal adrenals are susceptible to hemorrhage (identify this vs adrenal mass on MRI)

Malignant tumors

• Adrenal metastasis
  • Mets are more common than primary adrenal ca
    • New adrenal mass with prior malignancy = met 50% of the time
  • Breast (20%), lung (40%), RCC, TCC, colon, esophageal, melanoma
• Adrenocortical carcinoma
  • Rare; poor prognosis, peak in 1st and then 4th to 5th decade
  • May be functional/nonfunctional (more functional in peds)
    • Cushings, virilization/feminizing (17-ketosteroids, DHEA), hyperaldosteronism
  • a/w Li-Fraumeni, Lynch, BWS, MEN I - should get genetic testing
  • Usually > 5 cm (90%), more common on left, can have IVC tumor extension.
    • Imaging - Irregular borders, necrosis, 30% with calcification
  • Advanced disease - treatment with mitotane (toxic; need steroid replacement), cisplatin, etoposide, doxorubicin (FIRM-ACT 2012)

Look for signs of functionality - Cushing's signs; hypertension, hypokalemia, pheo symptoms, virilization

Adrenal mass functional workup

adrenalmass.org - helpful workup/management algorithms

• If suspect pheo (e.g. HU > 10 on noncon) - don't do dex suppression testing as this can trigger catecholaminergic crisis

Adrenal mass imaging characteristics 

• CT adrenal protocol
  • Thin cuts; phases - noncon, 1 min after contrast, 10-15 min after contrast (washout) (timing is a bit longer than normal renal protocol)
  • Look for: size, HU at each phase 
    • Intracytoplasmic fat high in adenoma, rare in mets, pheos, ACC
    • If HU < 10 on non-con, specificity for benign adenoma is ~ 100%, so don't really need further contrast in study (otherwise proceed with adrenal protocol)
• MR - slightly more accurate/sens/spec than CT
• Other - bMIBG can localize pheo/eval for mets

Characteristic imaging findings

Biopsy - only if would change management. But must exclude pheo first with biochemical tests.

Indications for surgery - functional, or concern for malignancy

Follow-up for benign non-functional masses:

• Imaging at 6, 12, 24 months
• If < 3 cm - no repeat functional workup needed
• If > 3 cm - repeat functional workup annually x 4 years (20% can become active)
• Adrenalectomy if grows > 1 cm or becomes functional

Surgical considerations

• Contralateral adrenal may have been suppressed so could require post-op steroids
• Aldosteronoma
  • Pre-op - K-sparing diuretics
  • ~ 50% still need BP meds afterwards, but overall surgery is more cost effective than medical management of aldosteronoma
  • If 2/2 bilateral hyperplasia - treat with spironolactone, not surgery
• Cushing's
  • Pre-op - stress dose steroids; tight glycemic control
  • For bilateral adrenalectomy (e.g. Cushing's disease failed pituitary resection) - typically do staged with two separate surgeries
• Pheochromocytoma
  • Alpha blockers (phenoxybenzamine irreversible blockade) + hydration (consider admitting night before for fluids)
    • Must be given before beta blockers to avoid over-activation of alpha receptors -> vasoconstriction, heart failure
  • If BP not controlled (want to err towards side of orthostatic hypotension), consider adding CCB, beta blockers, metyrosine) 
  • Can be sympathetically collapsed so watch out for BP/volume
    • 
  • ICU afterwards - watch for hypotension, rebound hypoglycemia. Repeat metabolic test in 2 wks should be normal.
• Adrenal cortical carcinoma
  • Tumor is very fragile/avoid capsule rupture - consider doing it open
  • Consider adjuvant mitotane if high-risk features (ADJUVO trial 2022)
• Adrenal myelolipoma
  • Surgery rarely indicated unless causing symptomatic mass effect, or acute hemorrhage (rare - 1%)
  • Lancet review of adrenal myelolipomas
  • Long-term follow-up: Growth > 1 cm and size > 6 cm associated with higher rate of hemorrhage
  • ESES/ENSAT 2023 guidelines R4.2: "We recommend against performing surgery in patients with an asymptomatic, nonfunctioning unilateral adrenal mass and obvious benign features on imaging studies"

Vascular supply (find the renal hilum first for landmarks)

• Arterial supply
  • Superior suprarenal (inferior phrenic) - main supply
  • Middle suprarenal (abdominal aorta)
  • Inferior suprarenal (renal)
• Venous drainage
  • R vein - short (< 5 mm) and directly into posterior IVC (near liver edge) - dangerous, fragile
  • L vein - longer (3 cm), off of L renal vein or L inferior phrenic vein, courses along medial side of adrenal. Close to SMA, splenic artery, tail of pancreas