Prolactinoma localization by inferior petrosal sinus sampling: illustrative case

Area of Science:

• Endocrinology
• Neurosurgery
• Diagnostic Imaging

Background:

• Inferior petrosal sinus sampling (IPSS) is standard for differentiating ectopic ACTH production from Cushing disease.
• The application of IPSS beyond ACTH-dependent hypercortisolism is infrequently documented.
• This study explores IPSS for localizing a prolactin (PRL)-secreting adenoma in a patient with hyperprolactinemia and multiple pituitary lesions.

Purpose of the Study:

• To evaluate the utility of IPSS in localizing a prolactinoma in a patient with bilateral pituitary lesions.
• To assess the effectiveness of IPSS in guiding surgical intervention for complex hyperprolactinemia cases.

Main Methods:

• A 37-year-old female with symptomatic hyperprolactinemia refractory to medical management presented with two pituitary lesions on MRI.
• Inferior petrosal sinus sampling (IPSS) was performed, measuring both PRL and ACTH levels.
• Lateralization of PRL hypersecretion was determined using absolute and ACTH-normalized PRL levels.

Main Results:

• IPSS data indicated significant PRL hypersecretion from the right-sided pituitary lesion.
• The patient underwent successful endoscopic resection of the right-sided lesion, confirmed as a prolactinoma.
• The patient achieved remission 2.5 years post-surgery without complications.

Conclusions:

• Inferior petrosal sinus sampling (IPSS) can be a valuable tool for lateralizing prolactinomas in patients with hyperprolactinemia and multiple sellar masses.
• This technique aids in surgical decision-making, particularly when distinguishing between bilateral pituitary lesions.
• IPSS offers a potential solution for complex cases of hyperprolactinemia requiring precise localization.