Surgical Disease of the Adrenal Gland (Part I)
Roc McCarthy, D.O.
• Anatomy• Physiology• The incidental adrenal mass• Fun facts• Pheochromocytoma
Adrenal Gland
• Cortex - mesoderm• Medulla - neuroectoderm• Renal agenesis, found in normal anatomic
position• Size- 5 x 3 x 1 x 5 cm• Retroperitoneal structure, contained in its
own sub-compartment w/in Gerota’s fascia
Adrenal Gland• Blood supply
Arterial - receives 7cc/gram minute - 3 arterial sources of flow: 1. Inferior phrenic artery 2. Aorta
3. Renal arteryVenous – single main vein most
important surgical structure- right → post IVC
- left → renal vein
Nerve Supply
• Medulla - sympathetic branches - epinephrine - norepinephrine
• Cortex – none• Lymphatics- lateral aortics (renal
artery to diaphragm)
Hypothalamic-Pituitary-Adrenal Axis
Layers of Adrenal Gland
Aldosterone• Primary stimulus for release is angiotensin II• Other: ACTH, low serum Na, elevated K, JGA via low
kidney perfusion
Adrenal Medulla
• Distinct from cortex embryologically (neuroectoderm)
• Secretes catecholamines sympathetic stimulation (mainly epinephrine but also norepinephrine and dopamine)
• If pt. has excess of BOTH epi and norepi, the tumor is in the adrenal gland
The Incidental Adrenal Tumor• 0.5 – 5% of abdominal CTs show abnormal
adrenal glands• 85% of adrenal masses are nonfunctional and
BENIGN• Def. of incidental mass:
- >1cm - discovered on exam for non-adrenal cause - absence of signs or symptoms of adrenal disorder
Questions to be asked:• Is the mass functional?• Any physical signs or symptoms?• Is there biochemical evidence of activity: 1.
Pheo screen 2. Potassium level 3. Glucocorticoid screen
• Is the mass malignant?• Any history of another malignancy?• Is imaging suggestive of malignancy?
Nature of Incidentally Found Adrenal Masses
• Review of 2,005 incidentally-discovered adrenal masses: - Nonfunctioning adenoma 82% - Functioning: Cushing’s 5%
Pheo 5% Aldosteronoma 1% -
Malignancy: Metastasis 3% ACC 4%
• Young WF, et al. Endocrinol Clin N Am. 2000
Good to Know Facts!
• If the adrenal gland has fat density material, it is by definition a benign myelolipoma
• If pt. has a known primary cancer, the adrenal mass with be mets from that site 50% of time
• Overall 2-4% of adrenal masses are ACC• If mass >6cm, ACC 65%
Incidental Adrenal Mass Initial Evaluation
• History and physical exam• Look for signs of hormonal syndromes• Search for occult malignancy• CXR• Stool for occult blood• Mammogram (women only)
Extent of Endocrine Evaluation?• Serum K (if HTN) → Conn’s• Plasma metanephrines: most sensitive test for
pheo• 24-hr urine cortisol (Cushing’s)
Diagnosis: Imaging• Rare for a nonfunctional adenoma to become
functional• MRI- Both ACC and pheo are hyper-intense in
T2 images (light up from T1 to T2)
CT Adenoma Characteristics• Sharp margins• Smooth, homogenous, lipid rich• Most <10 Hu on noncontrast images• Washout >50% @ 15 min
Incidental Adrenal Mass Management
• Hormonally active → surgical removal• > 5 cm → removal (with a scalpel)• < 3 cm observe• Surveillance Recommendations:
Old: - CT at 6 months - Annual endocrine eval for 4 years New: If mass stable on scans @ 3m and 1 yr then no further workup
Pheochromocytoma• Incidence and Presentation -
symptoms → release of epi/norepi - hypertension present 90% cases - orthostatic hypotension (low plasma vol) - 30% of pheo’s found at autopsy and cause of death cardiovascular disease - micturition syncope
Pheo (cont’d)• Triad: headache, tachycardia, diaphoresis• Other symptoms: Pallor, flushing, palpitations,
abd/chest pain, weakness, N/V, psychosis• Small tumors more likely symptomatic• ALL patients regardless of age, have a
complete cardiac work-up before surgery
Pheochromocytoma Rule’s of 10
• Bilateral• Familial (non-sporadic)• Pediatric• Malignant• Normotensive• Extra-adrenal• Multiple• *Childhood presentation breaks the rules- 25%
bilateral, multiple, extra-adrenal
Pheo- The Diagnosis
• Plasma free metanephrines- most sensitive test-seen 99% of patients
• 24° urinary catecholamines (2x normal is diagnostic)
• VMA• Clonidine suppression test (0.3mg oral, test 3 hrs
later) >50% reduction catecholamines NO pheo
MEN I
MEN IIA
MEN IIB
Pre-op Management
• Early alpha blockade???• Goal to control hypertension- phenoxybenzamine• Do NOT use b-blocker before alpha• IV hydration• Prevent cardiac arrhythmias
Pheo
• Post-op- hypotension (most common) sec to secondary to hypovolemia
• Surgical outcomes- excision does NOT always lead to long- term cure - recurrence 5% benign
10% malignant
Part II• Conn’s syndrome• Cushing’s syndrome• Addison’s disease• Adrenal cortical carcinoma• Metastatic disease to adrenal gland• Principles of adrenalectomy