Superficial siderosis of the central nervous system due to chronic hemorrhage from a giant invasive prolactinoma

Superficial siderosis of the central nervous system (CNS) is a rare disorder caused by deposition of hemosiderin in neuronal tissue in the subpial layer of the CNS due to slow subarachnoid or intraventricular hemorrhage. The most common neurologic manifestations include progressive gait ataxia, sensorineural hearing loss, and corticospinal tract signs. We present a case of superficial siderosis in a 43-year-old man who presented to the Emergency Department with sudden onset bilateral visual deterioration and a loss of consciousness. A hemorrhagic giant prolactinoma was diagnosed based on brain CT scan, T1-weighted MRI, and an endocrine blood examination. Susceptibility- weighted non-contrast MRI showed pathognomonic signs of superficial siderosis in the form of a hypointensity rim surrounding the brainstem, cerebellar fissures, and cranial nerves VII and VIII. This report demonstrates that superficial siderosis can be caused by pituitary apoplexy.