Petrosal sinus sampling for Cushing syndrome: anatomical and technical considerations. Work in progress

Area of Science:

• Endocrinology
• Neurosurgery
• Diagnostic Imaging

Background:

• Adrenocorticotropic hormone (ACTH)-producing pituitary microadenomas are a common cause of Cushing syndrome.
• Distinguishing pituitary ACTH sources from ectopic sources is critical for appropriate patient management.
• Current diagnostic protocols emphasize the importance of accurate localization of ACTH-secreting tumors.

Observation:

• ACTH-producing microadenomas of the pituitary gland exhibit unilateral drainage into the cavernous sinus.
• A single negative sample from inferior petrosal sinus sampling does not rule out a contralateral microadenoma.
• Large pituitary adenomas typically result in bilateral elevation of ACTH in the petrosal sinuses.

Findings:

• Bilateral inferior petrosal sinus sampling is essential for accurately diagnosing pituitary versus ectopic ACTH syndromes.
• Hemiresection of the pituitary may be guided by bilateral sampling results for small, surgically undetectable adenomas.
• Inferior petrosal sinus sampling is not indicated when imaging findings for Cushing syndrome are unequivocally positive.

Implications:

• Accurate diagnosis through bilateral sampling improves treatment selection and patient outcomes.
• Understanding unilateral drainage patterns enhances the interpretation of diagnostic tests.
• This approach minimizes misdiagnosis and unnecessary interventions for ACTH-dependent Cushing syndrome.