Surgical Disease of the Adrenal Gland (Part I)

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Surgical Disease of the Adrenal Gland (Part I)

• Roc McCarthy, D.O.

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• Anatomy
• Physiology
• The incidental adrenal mass
• Fun facts
• Pheochromocytoma

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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 Gerotas fascia

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Adrenal Gland

• Blood supply Arterial - receives 7cc/gram
  minute - 3 arterial sources of flow 1.
  Inferior phrenic artery 2. Aorta 3.
  Renal artery Venous single main vein most
  important surgical structure
• - right ? post IVC - left ? renal vein

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Nerve Supply

• Medulla - sympathetic branches -
  epinephrine - norepinephrine
• Cortex none
• Lymphatics- lateral aortics (renal
  artery to diaphragm)

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Hypothalamic-Pituitary-Adrenal Axis
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Layers of Adrenal Gland
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Aldosterone

• Primary stimulus for release is angiotensin II
• Other ACTH, low serum Na, elevated K, JGA via
  low kidney perfusion

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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

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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 - gt1cm
  - discovered on exam for non-adrenal cause
  - absence of signs or symptoms of
  adrenal disorder

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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?

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Nature of Incidentally Found Adrenal Masses

• Review of 2,005 incidentally-discovered adrenal
  masses - Nonfunctioning adenoma 82 -
  Functioning Cushings 5
  Pheo 5
  Aldosteronoma 1 - Malignancy Metastasis
  3 ACC 4
• Young WF, et al. Endocrinol Clin N Am. 2000

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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 gt6cm, ACC 65

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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)

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Extent of Endocrine Evaluation?

• Serum K (if HTN) ? Conns
• Plasma metanephrines most sensitive test for
  pheo
• 24-hr urine cortisol (Cushings)

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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)

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CT Adenoma Characteristics

• Sharp margins
• Smooth, homogenous, lipid rich
• Most lt10 Hu on noncontrast images
• Washout gt50 _at_ 15 min

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Incidental Adrenal Mass Management

• Hormonally active ? surgical removal
• gt 5 cm ? removal (with a scalpel)
• lt 3 cm observe
• Surveillance Recommendations Old - CT at 6
  months - Annual endocrine eval for 4
  years New If mass stable on scans _at_ 3m and 1
  yr then no further workup

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Pheochromocytoma

• Incidence and Presentation - symptoms ?
  release of epi/norepi - hypertension present 90
  cases - orthostatic hypotension (low plasma
  vol) - 30 of pheos found at autopsy and
  cause of death cardiovascular disease -
  micturition syncope

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Pheo (contd)

• 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

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Pheochromocytoma Rules of 10

• Bilateral
• Familial (non-sporadic)
• Pediatric
• Malignant
• Normotensive
• Extra-adrenal
• Multiple
• Childhood presentation breaks the rules- 25
  bilateral, multiple, extra-adrenal

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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) gt50 reduction catecholamines NO pheo

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MEN I
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MEN IIA
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MEN IIB
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Pre-op Management

• Early alpha blockade???
• Goal to control hypertension- phenoxybenzamine
• Do NOT use b-blocker before alpha
• IV hydration
• Prevent cardiac arrhythmias

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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

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Part II

• Conns syndrome
• Cushings syndrome
• Addisons disease
• Adrenal cortical carcinoma
• Metastatic disease to adrenal gland
• Principles of adrenalectomy