Adrenal incidentaloma

bySupphachoke Khemla MD.Supphawatana phaphun

MD.20 March 2552

Cross Sectional Anatomy

• Normal size (Lt or Rt adrenal) : 3 cm × 6 mm

• Retroperitoneum organ• Gerota’s fascia : connect the gland to

upper pole of the kidney

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 ?

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%)

Prevalence• The Mayo clinic 2,066 cases : - 50% metastasis cancer - 25% other known lesions - 7.5% symptomatic tumors - 16.5% incidental (include nodules <

1cm) - Overall incidental adrenal tumor (> 1cm) = 0.4 %

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

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

Cushing’s - ACTH-independent bilateral macronodular adrenal

hyperplasia

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 +++

Evaluate for malignancy

• Primary adrenal carcinoma : quite rare

• Others : - metastasis (particularly lung cancers)• Evaluate : size and imaging

characteristics (imaging phenotype)

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% > 4 cm

Size

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

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)

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 < 10 HU on unenhanced CT (ie, has density of fat) likelihood benign adenoma 100 %

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 > 50 % ( 100% sensitivity & specificity)

if compared with carcinomas, metastasis or pheochromocytoma

CT scan

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

MRI

• Although CT : primary adrenal imaging• MRI has advantages in certain clinical

situations• Several difference MRI1. - conventional spin-echo MRI - was the first - T1 and T2 - distinguish benign adenomas

from malignancy and

pheochromocytoma

MRI

2- gadolinium-DPTA-enhanced MRI - adenoma : mild enhancement and

rapid washout of contrast - malignancy : rapid and marked enhancement and a slower washout pattern

MRI3 - 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

MRI

• Interpretation - benign adrenal cortical adenoma :

lose signal on out-of-phase images, but appear relatively bright on in-phase images

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

Others

• PET (Positron emission tomography) - FDG-PET and MTO-PET are not

recommend (cost and insufficiency data to

support their routine use)

Imaging characteristics

Benign adenoma

• Benign cortical adenoma• Round & homogenous density < 4 cm, unilateral• low unenhanced CT

attenuate values (<10HU)• Rapid contrast washout (10

min)• Absolute contrast washout

>50%• Isointensity with liver on both

T-1 & T-2 (MRI)• Chemical shift : lipid on MRI

Pheochromocytoma

• Increase attenuate on nonenhanced CT (>20HU)

• Increase mass vascularity• Delayed contrast

washout (<10 cm)• Absolute contrast

washout <50 %• High signal intensity on T-

2 MRI• Cystic and hemorrhage • Variable size

Pheochromocytoma

Adrenocortical carcinoma• Irregular shape• Inhomogenous density (central

necrosis) > 4 cm, unilateral, calcify• High unenhanced CT (>20HU)• Delayed contrast washout (10

min)• Absolute contrast washout < 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.

Metastasis

• Irregular, inhomogenous• Bilateral• High enhanced CT (>20 HU)• Enhancement with contrast• Delayed contrast washout (10 min)• Absolute contrast washout < 50%• Isointensity or slightly less intense than liver T-1 ,

high to intermediate intensity T-2 MRI (represent water increase)

Others

• Adrenal cysts• Adrenal hemorrhage• myelolipoma

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

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.

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 .

• 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)

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.

• Screening test is measurement of plasma free metanephrines or 24 hr urine metanephrine .

• Plasma free metanephrines is 99% sensitive.

• Not very specific 85-89%

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 .

• 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

• 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

– Disturbed cortisol circadian rhythm in 43 percent

– Blunted plasma ACTH responses to corticotropin-releasing hormone in 55 percent

• If the post-overnight DST

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

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.

Management of adrenal incidentaloma

Clinical and CTapperance

investigation

Treatment

F/U

True cyst

Aspirate?

Repeat CT at 1 yr

adrenolipoma

resect

or

Metastasiscarcinoma

FNAB

Metastasia CA

Resect if appropriate

Diagnosis unclear

Non fuctioning functioning

BPserumK

CatecholamineOvernigth 1 gm DSTUrine 17 OHCS 17KS

FNA < 6 CM > 6CM

Adenal tissue

resect resect

Repeat CT at 2,8,18 mo

• 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.

Bilateral adrenal masses 

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

SUMMARY

• All patients should be evaluated for subclinical hormonal hyperfunction and cancer.

• History and physical examination are important in the initial assessment.

Benign cortical adenoma. A homogeneous adrenal mass <4 cm in

diameter, with a smooth border, and an attenuation value <10 HU on

unenhanced CT, and rapid contrast medium washout (eg,

>50 percent at 10 minutes)

The imaging suggest adrenal carcinoma or metastases include: irregular shape. inhomogeneous density. high unenhanced CT attenuation values

(>20 HU), delayed contrast medium washout (eg, <50 percent at 10 minutes),

diameter >4 cm, and tumor calcification. Other characteristics are described above.

• 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

• 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.

• 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 .

THANK YOU