A 30-year-old woman has amenorrhea, galactorrhea, and a serum prolactin of 90 ng/mL. MRI shows a normal sized pituitary fossa with a 4 mm hypothalamic mass abutting the stalk. A second patient has identical symptoms with prolactin of 320 ng/mL and a 12 mm sellar mass. The correct interpretation is:

• A The first has stalk effect and the second has a true prolactinoma ✓
• B Both patients have prolactin-secreting microadenomas
• C The first has a macroprolactinoma and the second has stalk compression
• D Both findings are consistent with empty sella syndrome

Explanation

Any mass compressing the pituitary stalk interrupts dopaminergic inhibition, raising prolactin modestly, typically below 150 to 200 ng/mL. Values above roughly 200 ng/mL in the presence of a macroadenoma indicate a genuine lactotroph adenoma. This distinction matters because stalk effect lesions need treatment of the underlying mass, not dopamine agonists alone. Empty sella does not produce a discrete hypothalamic mass or these hormonal patterns.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.