Proptosis as the presenting sign of giant prolactinoma in a prepubertal boy: successful resolution of hydrocephalus by use of medical therapy.

We report the case of a 13-year-old prepubertal boy who presented with a left-sided proptosis, bilateral papilloedema and hydrocephalus who was subsequently diagnosed with a giant prolactinoma invading the left orbit. He was commenced on dopamine receptor agonists in the form of quinagolide and cabergoline, and made an excellent response to medical therapy alone, with resolution of hydrocephalus, restoration of normal vision and a 98% reduction in serum prolactin. The rapid improvement achieved negated the requirement for surgery and this highlights the efficacy of the dopamine agonists in the management of giant prolactinomas, even in the presence of neurological symptoms.