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