2. Incidentaloma
Definition
Adrenal incidentalomas are unsuspected
adrenal masses greater than 1 cm in
diameter identified on cross-sectional
imaging performed for seemingly unrelated
causes
Frequency of adrenal incidentalomas is
relatively high, with reporting an incidence
of approximately 5%
3. Incidence of the incidental adrenal mass
increases with age,with a risk of less than
0.5% in individuals in their 20s and up to
7% in those 70 years of age or older
Nearly 20% of adrenal incidentalomas are
found to be potential surgical lesions
The two characteristics of primary clinical
relevance are imaging and metabolic activity
or functional status
4.
5. Imaging of Adrenal Masses
Ultrasonography is a suboptimal imaging
modality for detecting and fully
characterizing adrenal lesions
Ultrasonography is responsible for identifying
individuals with adenomas, right-sided lesions
appear to be more common.
6. Computed Tomography and
Magnetic Resonance Imaging.
CT and MRI permit cross-sectional and
reconstructed anatomic image
characterization of the adrenals and serve
as the cornerstone for adrenal evaluation.
Most adrenal incidentalomas are small
homogeneous masses with regular
contours that cannot be immediately given
a pathologic label.
7. An unenhanced CT scan is the first, and
perhaps single best, and most easily
interpreted test for intracellular lipid and
therefore can diagnose an adrenal
adenoma in more than 70% of cases.
Low attenuation (<10 HU) on unenhanced
CT corresponds to high intracytoplasmic
lipid content and is diagnostic for an
adrenal adenoma
8. Despite the high specificity of the 10-HU cutoff,
few low-density (<10 HU) pheochromocytomas
have been reported, underscoring the
importance of a metabolic workup for all
adrenal lesions
CECT -Irregular margins and an enhancing rim
can be quite specific for malignancy
9. Computed Tomography Washout
Study
Approximately 30% of adrenal adenomas
exhibit an attenuation of greater than 10 HU
on unenhanced CT owing to their lower
lipid content.
These “atypical adenomas” are
indistinguishable from nonadenomas on
noncontrast CT density measurements
alone
Fortunately, lipid-poor adenomas possess
identical properties to lipid-rich adenomas
regarding their rapid loss (washout) of
enhancement after CT contrast load
10. An absolute percent washout (comparing
noncontrast values with 15-minute
postcontrast density values) of greater than
60%, or a relative percent washout (RPW)
(comparing arterial phase density
measurements with 15-minute postcontrast
density values) of greater than 40% on
delayed (washout) imaging, is indicative of
adenoma
11. MRI
MRI harnesses the interference between
signal collected from fat and water tissue
to evaluate for intracellular lipid content
On such opposed phase chemical shift
imaging, signal intensity loss on out-of-
phase sequences, when compared with in-
phase imaging, signifies the presence of
intracellular lipid and definitively identifies
the lesions in question is an adenoma
12.
13. Nevertheless, CT washout studies are
considered the gold standard and appear
to surpass opposed phase chemical shift
MRI in their sensitivity for identifying
adenomas
MIBG imaging has a limited role in the routine
evaluation of adrenal incidentalomas.
FDG PET is best reserved for cases in which
CT imaging and clinical data are inconclusive
14. Biopsy of Adrenal Masses
The role of adrenal biopsy has been limited
for the followingreasons:
(1) modern imaging in the context of
clinical characteristics affords superb
diagnostic capabilities,
(2) histologically,adenomas cannot be
reliably differentiated from adrenal
carcinomas,
(3) adrenal biopsy is not without risk
15. Adrenal biopsy should be pursued only
when limitations of imaging have been
reached and when the physician and
patient are certain that the result of biopsy
will influence management.
When used to differentiate benign from
metastatic disease, adrenal biopsy carries
favorable test characteristics.
16. Size and Growth
A relationship does exist between the size
of an adrenal lesion and its malignant
potential, with larger masses more likely to
exhibit adverse clinical and pathologic
features
Masses that exceed 6 cm should be
considered malignant until proven benign,
which usually requires definitive resection.
17. Although management of masses between 4
cm and 6 cm is controversial, thought leaders
in the field advise that in otherwise healthy
individuals, masses 4 cm or larger should be
resected.
Kinetics of growth should be followed. The
current recommendation is to resect masses
that grow over 1 cm;
18. Assessment of Function of
Adrenal Masses
The NIH consensus statement
recommends metabolic testing for all
adrenal incidentalomas
Current practice is to test all new adrenal
masses for cortisol and catecholamine
hypersecretion. In patients with a history of
hypertension, aldosterone hypersecretion
should also assessed
19. Testing for Cortisol
Hypersecretion
Three first-line tests are available to screen
patients with incidentalomas for Cushing
syndrome:
(1)LD-DST,
(2) a late-night salivary cortisol test, and
(3) a 24-hour UFC evaluation.
20. Testing for Aldosterone
Hypersecretion
The screening test of choice for Conn
syndrome is the ratio of morning plasma
aldosterone (ng/dL) to renin (ng/mL/hr).
An ARR of 20 (some suggest 30) along with
a concomitant aldosterone concentration
above 15 ng/mL is indicative of Conn
syndrome
21. Testing for Catecholamine
hypersecretion
Free fractionated plasma metanephrines
and the 24-hour urinary fractionated
metanephrine test constitute the mainstay
for pheochromocytoma testing.
Acetaminophen can produce a false-
positive result owing to cross reactivity in
the assay and should be stopped for at
least 5 days before testing
22. Testing for Adrenal Sex Steroid
Hypersecretion
Hypersecretion of adrenal sex steroids by
adrenal masses, especially incidentalomas, is
exceedingly rare.
The most common adrenal mass that
hypersecretes sex steroid is an adrenal
carcinoma that concomitantly exhibits cortisol
hypersecretion
Routine testing of incidentalomas for sex
hormones is currently not recommended
