Adrenal incidentaloma

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Adrenal incidentaloma

• by
• Supphachoke Khemla MD.
• Supphawatana phaphun MD.
• 20 March 2552

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Cross Sectional Anatomy

• Normal size (Lt or Rt adrenal) 3 cm 6 mm
• Retroperitoneum organ
• Gerotas fascia connect the gland to upper pole
  of the kidney

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Introduction

• Mass lesion greater than 1 cm.
• Serendipitiously discovered by radiologic
  examinations
• Such as - Computed tomography (CT)
• - Magnetic resonance imaging
  (MRI)
• Two questions
• - Is it malignancy ?
• - Is it functioning ?

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Prevalence

• Autopsy Total 739 cases
• (adrenal masses between 2 mm 4 cm)
• - 9 normotensive
• - 12 hypertension
• The Mayo clinic
• - 61,054 abdominal CT scans
• - 1985 1990
• - adrenal masses 2,066 cases (3.4)

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Prevalence

• The Mayo clinic
• 2,066 cases
• - 50 metastasis cancer
• - 25 other known lesions
• - 7.5 symptomatic tumors
• - 16.5 incidental (include nodules lt 1cm)
• - Overall incidental adrenal tumor
• (gt 1cm) 0.4

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Prevalence

• Recent study high resolution scanner
• - report prevalence from CT abdomen 4.4
• Demonstration enlarged unusually shaped
• 1. one adrenal mass
• 2. bilateral adrenal masses

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Bilateral masses

• Studies 887 and 202 cases (with adrenal
  incidentaloma)
• - bilateral 10-15
• - causes
• - metastasis
  - pheochromocytoma
• - congenital adrenal hyperplasia
  - amyloidosis
• - cortical adenoma
  - infiltrative disease of adrenal gl.
• - lymphoma
  - Infections TB, fungus
• - hemorrhage
  - ACTH-dependent Cushings
• - ACTH-independent bilateral
  macronodular adrenal hyperplasia

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Bilateral masses

• One adrenal mass non-functioning cortical
  adenoma
• Contralateral adrenal mass hormone secreting
• All patients with bilateral adrenal masses
  should be screened for adrenocortical hyper/hypo
  function

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Evaluate for malignancy

• Primary adrenal carcinoma quite rare
• Others - metastasis
• (particularly lung cancers)
• Evaluate size and imaging characteristics
  (imaging phenotype)

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Size

• The maximum diameter is predictive of malignancy
• Important if the smaller is at the time of
  diagnosis, the better overall prognosis
• Adenocortical carcinomas
• - significantly asso. with mass size
• - 90 gt 4 cm

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Size

• The National Italian Study Groups
• - 4 cm cutoff
• - sensitivity 93
• - specificity 76

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Imaging phenotype

• MRI or CT
• 3-5 mm. cuts predict histological type of
  adrenal tumor
• Characteristics of the mass
• example lipid-rich nature of cortical
  adenomas
• (benign tumor)

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CT scan

• Density (black is less dense)
• Spectrum Air -black, Bone-white
• Hounfield scale is a semiquantitative method of
  measuring x-ray attenuation
• Typical precontrast Hounsfield unit (HU) valves
• adipose tissue -20 to 150 HU
• kidney 20 to 150 HU
• if adrenal mass lt 10 HU on unenhanced CT
• (ie, has density of fat)? likelihood
  benign
• adenoma 100

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CT scan

• contrast-enhanced CT
• - adenoma rapid contrast medium washout
• - non-adenoma delayed contrast medium
  washout
• 10 mins after administration pf contrast
• - adenoma absolute contrast media washout
  gt 50 ( 100 sensitivity specificity)
• if compared with carcinomas, metastasis or
  pheochromocytoma

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CT scan

• Imaging phenotype does not predict hormone
  function, it can predict underlying pathology,
  and surgical resection

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MRI

• Although CT primary adrenal imaging
• MRI has advantages in certain clinical situations
• Several difference MRI
• 1. - conventional spin-echo MRI
• - was the first
• - T1 and T2
• - distinguish benign adenomas from
• malignancy and pheochromocytoma

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MRI

• 2- gadolinium-DPTA-enhanced MRI
• - adenoma mild enhancement and
  rapid
• washout of contrast
• - malignancy rapid and marked
• enhancement and a slower washout
• pattern

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MRI

• 3 - Chemical shift imaging (CSI)
• - lipid sensitive imaging
• - principle hydrogen protons in water,
• lipid molecules
• - chemical shift technique
• 1. in-phase water lipid are aligned
• signal intensity
  high
• 2. out of phase opposite from each
  other
• signal intensity
  low

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MRI

• Interpretation
• - benign adrenal cortical adenoma lose
  signal on out-of-phase images, but appear
  relatively bright on in-phase images

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Others

• PET (Positron emission tomography)
• - fluoro-2-deoxy-D-glucose (FDG)
• - high sensitivity for detect malignancy
• - however 16 benign cortical lesions may
  
• have FDG-PET uptake
• - Metomidate (MTO) PET
• lack of MTO specific to non-adrenal
• cortical origin (metastasis
• pheochromocytoma

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Others

• PET (Positron emission tomography)
• - FDG-PET and MTO-PET are not recommend
• (cost and insufficiency data to support
  their
• routine use)

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Imaging characteristics
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Benign adenoma

• Benign cortical adenoma
• Round homogenous density
• ? lt 4 cm, unilateral
• low unenhanced CT attenuate values (lt10HU)
• Rapid contrast washout (10 min)
• Absolute contrast washout gt50
• Isointensity with liver on both T-1 T-2 (MRI)
• Chemical shift lipid on MRI

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Pheochromocytoma

• Increase attenuate on nonenhanced CT (gt20HU)
• Increase mass vascularity
• Delayed contrast washout
• (lt10 cm)
• Absolute contrast washout lt50
• High signal intensity on T-2 MRI
• Cystic and hemorrhage
• Variable size

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Pheochromocytoma
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Adrenocortical carcinoma

• Irregular shape
• Inhomogenous density (central necrosis)
• ?gt 4 cm, unilateral, calcify
• High unenhanced CT (gt20HU)
• Delayed contrast washout (10 min)
• Absolute contrast washout lt 50
• Hypointensity compared with liver T-1 and high to
  intermidiateintensity T-2 MRI
• High standard uptake value (SUV) on FDG-PET-CT
  study
• Evidence of local invasion or metas.

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Metastasis

• Irregular, inhomogenous
• Bilateral
• High enhanced CT (gt20 HU)
• Enhancement with contrast
• Delayed contrast washout (10 min)
• Absolute contrast washout lt 50
• Isointensity or slightly less intense than liver
  T-1 , high to intermediate intensity T-2 MRI
  (represent water increase)

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Others

• Adrenal cysts
• Adrenal hemorrhage
• myelolipoma

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Fine-needle aspiration biopsy

• Cannot distinguish a benign adrenal mass from the
  rare adrenal carcinoma
• Thus FNA biopsy
• - indicated a suspicion of cancer outside
  the adrenal gland
• - staging evaluation for a known cancer
• - not useful routine evaluation

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IS IT FUNCTIONAL?

• 6 - 20 of adrenal incidentalomas have hormonal
  abnormality.
• Hormonal hypersecretion is most likely in mass
  are at least 3 cm in diameter.
• Occurs mostly within the first 3 years after
  diagnosis.

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• 85 percent of the masses were non fuctioning.
• 9 percent secreted sufficient cortisol to produce
  subclinical Cushing's syndrome .
• 4 percent were pheochromocytomas (less than half
  caused hypertension) .
• 2 percent were aldosteronomas .

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• A careful personal and family history, review of
  systems, PE.
• At minimum for the following condition.
• Pheochromocytoma
• Cushing syndrome (including subclinical disease)
• Primary aldosteronism (only if hypertensive)

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Pheochromocytoma

• 3-10 of adrenal incidentalomas prove to be
  pheochromocytomas.
• Screening for pheochromocytoma is mandatory in
  all case.
• Because high rate morbidity and mortality.
• It is symptomatic up to 15 of case.

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• Screening test is measurement of plasma free
  metanephrines or 24 hr urine metanephrine .
• Plasma free metanephrines is 99 sensitive.
• Not very specific 85-89

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Cushing syndrome

• 5-20 of pt with adrenal incidentaloma are report
  to have subclinical Cushing syndrome.
• Subclinical Cushing's syndrome
• mild hypercortisolism without clinical
  manifestations of Cushing's syndrome .
• most frequent hormonal abnormality detected in
  patients with adrenal incidentalomas .

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• In 2002 ,a National institutes of Health
  consensus panel recommened a 1 mg over night
  dexamethasone supression test.
• Lack of supression interfering condition.
• Decrease dexamethason absorbtion.
• Drug barbiturate, phenyltoin, carbamazepine,
  rifampicin.
• Increase concentration of corticosteroid-binding
  globulin
• Pseudo Cushhig state

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• Hormonal evaluation in subclinical Cushing's
  syndrome showed the following
• Low baseline secretion of corticotropine (ACTH)
  in 79 percent
• Lack of suppressibility of cortisol secretion
  after 1 mg dexamethasone in 73 percent
• Supranormal 24-hour urinary cortisol excretion in
  75 percent

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• Disturbed cortisol circadian rhythm in 43 percent
  
• Blunted plasma ACTH responses to
  corticotropin-releasing hormone in 55 percent

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• If the post-overnight DST
• Then baseline serum ACTH, two-day high-dose DST
  is indicated to confirm the excess hormone
  secretion.

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Primary Hyperaldosteronism

• 1.6-3.8 of adrenal incidentalomas.
• Pt with hypertension should be evaluated for
  primary aldosteronism.
• Hypokalemia suggest aldosteronism.
• Normal K not exclude.
• The best screening test is the ratio of the
  plasma aldosterone to the plasma renin activity.

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Management of adrenal incidentaloma
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Clinical and CT apperance
True cyst
adrenolipoma
Metastasis carcinoma
FNAB
investigation
Metastasia CA
resect
Aspirate?
Treatment
or
F/U
Resect if appropriate
Repeat CT at 1 yr
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Diagnosis unclear
BP serumK Catecholamine Overnigth 1 gm DST Urine
17 OHCS 17KS
Non fuctioning
functioning
FNA lt 6 CM
gt 6CM
Adenal tissue
resect
resect
Repeat CT at 2,8,18 mo
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• subclinical Cushing's syndrome and unilateral
  adrenalectomy?
• absence of a prospective randomized study
• candidates for adrenalectomy.
• who have attributable to excess glucocorticoid
  secretion (eg, recent onset of hypertension,
  diabetes, obesity, and low bone mass)
• lack of suppression to both an overnight DST) and
  a two-day high-dose DST.

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Bilateral adrenal masses 

• The management of bilateral adrenal masses is
  different from that for unilateral masses.

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SUMMARY

• All patients should be evaluated for subclinical
  hormonal hyperfunction and cancer.
• History and physical examination are important in
  the initial assessment.

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• Benign cortical adenoma.
• A homogeneous adrenal mass lt4 cm in diameter,
• with a smooth border,
• and an attenuation value lt10 HU on unenhanced CT,
  
• and rapid contrast medium washout (eg, gt50
  percent at 10 minutes)

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• The imaging suggest adrenal carcinoma or
  metastases include
• irregular shape.
• inhomogeneous density.
• high unenhanced CT attenuation values (gt20 HU),
  delayed contrast medium washout (eg, lt50 percent
  at 10 minutes),
• diameter gt4 cm, and tumor calcification. Other
  characteristics are described above.

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• Pheochromocytoma should be excluded by measuring
  24-hour urinary fractionated metanephrines and
  catecholamines.
• Subclinical Cushing's syndrome should be ruled
  out by the 1-mg overnight dexamethasone.
• primary aldosteronism. should be screen in
  patient is hypertensive by a plasma
  aldosterone-to-plasma renin activity ratio and
  plasma potassium concentration

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• Recommend surgery pheochromocytoma,
  aldosteronoma.
• Suggest surgery for patients with subclinical
  Cushing's syndrome who are younger and who have
  disorders potentially attributable to autonomous
  glucocorticoid secretion.

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• Suggest surgery for patients with adrenal masses
  greater than 4 cm in diameter .
• If there is evidence of metastasis and after
  excluding pheochromocytoma with biochemical
  testing, suggest performing a diagnostic
  CT-guided FNA biopsy .

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THANK YOU
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