- A 2.1x1.5cm left adrenal mass was found on CT in a female patient complaining of bilateral flank pain. - The mass had an average attenuation of -15% on non-contrast CT and showed an absolute post-contrast washout of 70% and relative post-contrast washout of 113%. - These washout kinetics are characteristic of a benign adrenal adenoma.

1. Case - 3
• Name - M.B
• Age -
• Sex - F
• Clinical data - ? Nephrolithiasis
• Patient complains for bilateral flank pain.
• Pre and post contrast CT of the abdomen with adrenal protocol was
done.

2. Imaging finding
• There is a well defined low attenuating left adrenal mass with a
hyperdense focus. It measures 2z1.5 cm in size and has average
attenuation of about -15%
• Post contrast study
• Absolute post contrast washout - 70%
• Relative post contrast washout - 113%
• The right adrenal gland appears normal
• Prominent subcutanous fat seen in the abdominal wall.

3. Adrenal adenoma : overview
• The most common adrenal mass
• Even in patients with a primary tumor elsewhere
• CT -
• NCECT - attenuation - <10HU
• CECT -
• APW - >60%
• RPW - >40%
• RPW is more accurate than the APW
• 15 minute delay is more accurate than 10 minute delay.
• Wash out kinetics don’t depent on amount of intracellular lipid.

4. Adrenal Adenoma :
• Is it functioning?
• Why is it heterogenous.

5. Is it functioning.
• Majority of adrenal adenomas are non functioning ad
found as incidentalomas.
• There is no direct way of knowing on CT
• Indirect signs
• Atrophy of the contralateral adrenal gland.
• Excess fat proliferation.

7. Why is it heterogenous
• With increasing size, heterogeneity of adenoma increases

8. Adrenal adenoma with hemorrhage
• Not common
• non-traumatic intra-tumoral adrenal
hemorrhage has been reported in
about 0.3% to 1.8% of autopsies
• Hemorrhage within adrenal
adenoma usually occurs in patients
receiving anticoagulation therapy
• Imaging appearance will depend on
age of the bleed.

9. Adenoma with mylolipomatous degeneration
• Some adenomas undergo myelo-lipomatous metaplasia or
degeneration in which this lipid content becomes macroscopic

10. Mixed lipid poor and lipid rich adenoma
• Impossible to differentiate from collision tumor on unenhanced CT
• Wash out kinetics is key in the differentiation

12. Adrenal collision tumors
• Rare entities defined by two histologically separate tumors coexist in
the adrenal gland without significant histologic overlap or admixture.
• Most common collision tumors are that of adenoma and
myelolipoma.
• wide variety of combinations of adenomas, myelolipoma, pheochromocy
toma, adrenocortical carcinoma, and metastases have been described
• Most difficult senario is having a hyepervascular metastasis in the
setting of adrenal adenoma which may be impossible to differentiate
from mixed lipid poor and lipod rich adenoma.