Cushing Syndrome: Diagnostic Workup and Imaging Features, With Clinical and Pathologic Correlation

Area of Science:

• Endocrinology
• Medical Imaging

Background:

• Cushing syndrome (CS) is characterized by chronic excess cortisol exposure.
• It can be exogenous (glucocorticoid administration) or endogenous.
• Endogenous CS is classified as adrenocorticotropic hormone (ACTH)-dependent or ACTH-independent.

Purpose of the Study:

• To outline diagnostic approaches for Cushing syndrome.
• To differentiate between ACTH-dependent and ACTH-independent causes.

Main Methods:

• Utilizes diagnostic imaging techniques such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT).
• Includes specialized imaging protocols (e.g., adrenal protocol CT/MRI).
• May involve bilateral inferior petrosal sinus sampling and nuclear medicine tests.

Main Results:

• Pituitary MRI is diagnostic for Cushing disease (pituitary adenoma), the common cause of ACTH-dependent CS.
• Ectopic ACTH production (e.g., thoracic or abdominal tumors) requires CT, MRI, and nuclear medicine for localization.
• Adrenal abnormalities causing ACTH-independent CS are typically diagnosed with adrenal protocol CT or MRI.

Conclusions:

• Diagnostic imaging is crucial for pinpointing the source of cortisol excess in Cushing syndrome.
• Specific imaging modalities are selected based on whether the CS is ACTH-dependent or independent.
• Timely and accurate diagnosis through imaging aids in appropriate patient management.