Giant prolactinoma: An unusual case of obstructive hydrocephalus

Prolactinoma causing obstructive hydrocephalus is quite rare. We present a case of a 28-year-old previously healthy man who presented with sudden onset of dysarthria and expressive aphasia along with intense bifrontal headache and shortterm memory loss. Initial brain CT and brain MRI revealed a large 5.2 x 4.7 x 2.6 cm suprasellar mass, which extended to the third ventricle reaching up to the foramen of Monro and laterally displacing both internal carotid arteries. He was emergently placed an external ventricular drainage to relieve intracranial hypertension which led to immediate reversal of mental status as well as speech ability. His extensive endocrine work-up demonstrated a prolactin level with dilution of 12,650 μg/L (normal=2-18 μg/L) (549,996.7 pmol/L) consistent with the diagnosis of giant macroprolactinoma. Bromocriptine was initiated with successful tumor shrinkage and normalization of prolactin level within 7 months after initial presentation. Our case demonstrates the importance of obtaining a thorough hormonal evaluation of a large sellar lesion causing obstructive hydrocephalus to allow for an accurate diagnosis. It also demonstrates the effectiveness of medical therapy in the treatment of macroprolactinomas, even if very large. Medical treatment with dopamine agonists is still a first-line, effective approach with a favorable outcome in patients with giant macroprolactinomas causing intracranial hypertension and neurological symptoms as was the case in our patient.