Moyamoya disease presenting as galactorrhea

Moyamoya disease (MMD) is a progressive cerebrovascular condition marked by carotid narrowing and collateral vessel formation. Patients are often diagnosed after a stroke, but here we describe a case of galactorrhea as the presenting symptom of MMD. A 30-year-old gravida 1, para 0 woman noted milky, nonbloody discharge leaking from both breasts after manual compression during sexual intercourse. Prolactin was mildly elevated at 29.4 ng/mL (SI [International System of Units]: 29.4 µg/L) (reference range, 3-23.1 ng/mL [SI: 3-23.1 µg/L]). Magnetic resonance imaging of the pituitary gland showed no microadenoma but incidentally revealed a tortuous right internal carotid artery compressing the pituitary, raising the possibility of vascular compression contributing to galactorrhea and mild hyperprolactinemia. Magnetic resonance angiography and catheter angiography confirmed MMD. Mild cognitive impairment, persistent headaches, and secondary hypertension eventually necessitated neurosurgical revascularization. After surgery, the patient experienced a significant reduction in symptoms although challenges with memory and headaches have persisted. This case underscores the importance of brain imaging in evaluating hyperprolactinemia and highlights the potential for endocrinologic sequelae when MMD involves vessels in proximity to the pituitary gland.