Diagnostic Ultrasound - Abdomen and Pelvis

Adrenal Cyst
Diagnoses: Adrenal Gland
TERMINOLOGY
• Descriptive term for simple or complex cystic lesion in
adrenal gland
IMAGING
• General features: Well-defined, round, uni-/multilocular,
thin-walled, suprarenal cyst
• US: Avascular, anechoic or hypoechoic lesion with thin wall
and posterior acoustic enhancement
○ Low-level internal echoes, calcification, fluid-fluid levels,
and septations suggest recent hemorrhage
• CT: Nonenhancing, thin-walled, homogeneous, low-density
lesion with attenuation values < 20 HU
○ Higher or mixed attenuation cyst contents →
hemorrhage, intracystic debris, crystals; ± calcification
• MR: Nonenhancing with uniform low T1, high T2 SI
○ Hemorrhage shows variable T1 signal
• Concerning features: Complicated cyst, ≥ 5 cm size, internal
echogenicity, or thick wall (≥ 3 mm) → suspect malignancy
KEY FACTS
• Imaging recommendation
○ US for initial screening and follow-up
○ CT and MR for further characterization
TOP DIFFERENTIAL DIAGNOSES
• Necrotic adrenal tumor
• Adjacent cystic lesions
• Adrenal adenoma
CLINICAL ISSUES
• Typically clinically silent
• Often increases in size over time; not indicative of
malignancy
• Usually conservative management: No standard follow-up
imaging recommendations
• Treatment reserved for cysts with malignant features, > 5
cm, or in symptomatic patients with endocrine
abnormalities or complications
(Left) Sagittal transabdominal
ultrasound shows a wellcircumscribed
anechoic lesion
with a thin wall and posterior
acoustic enhancement ſt
immediately superior to the
right kidney, compatible with
an adrenal cyst. (Right)
Longitudinal transabdominal
ultrasound shows a welldefined
left adrenal cyst ſt.
Note adjacent spleen st.
(Left) Transverse oblique
transabdominal ultrasound
shows a complex, septated
cystic lesion ſt above the
right kidney (not included in
the field of view). Note the
hyperechoic foci st associated
with the septum and low-level
echoes in the smaller cystic
component . (Right)
Corresponding axial CT
confirms the cystic nature of
the complex lesion arising
from the right adrenal gland.
Note calcification associated
with the septum st. Upper
pole of the right kidney .
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