Obstructive Hydrocephalus, Fifth Nerve and Hypothalamus Involvement: Acute Presentation of a Giant Prolactinoma

INTRODUCTION: Pituitary tumors from lactotrope cells account for about 40% of all functioning pituitary cancers. Men tend to present with a larger, more invasive and rapid growth prolactinomas than women, possibly because hypogonadism features are less evident. CASE REPORT: A 27-year-old, previously asymptomatic Saudi man presented with a 3-day history of emesis with severe left-sided frontal headache, left face and right upper limb numbness, with signs of obstructive hydrocephalus. Brain Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) revealed a giant pituitary mass occupying several regions (sellar, infra-sellar, and supra-sellar) measuring 6.5 × 5.7 × 5.9 cm, and invading the sphenoid sinus as well as the cavernous sinuses bilaterally, with intra-pituitary hemorrhage compressing the third ventricle causing obstructive hydrocephalus. Prolactin levels were >200,000 mIU/L, consistent with invasive giant prolactinoma (IGP). He was treated with Cabergoline which eventually normalized the prolactin level and significantly reduced the size of IGP. CONCLUSION: This is a rare case of obstructive hydrocephalus with super-imposed intra-pituitary hemorrhage secondary to IGP, highlighting the importance of a full hormonal assessment for proper diagnosis and management.