An unusual cause of superficial siderosis of central nervous system: A case report of a vestibular schwannoma

Vestibular schwannomas are relatively common benign tumors that account for 7-8% of all intracranial tumors. There is a limited number of cases of subarachnoid hemorrhage associated with vestibular schwannoma in the literature. The incidence of symptomatic tumor bleeding is historically reported less than 1%. Susceptibility-weighted imaging (SWI) is a relatively new Magnetic Resonance Imaging (MRI) sequence that is highly sensitive to compounds which distort the local magnetic field such as blood products and hemorrhage. We herein report the rare MRI findings of a 53-year-old man with unilateral vestibular schwannoma and hearing loss who was followed for 4 years. Initial diagnosis of the vestibular schwannoma was made on prior conventional MRI. We included SWI sequence in routine brain MRI protocol. During follow-up, SWI demonstrated focal superficial siderosis due to recurrent subarachnoid hemorrhage seen as hypointense blooming artifacts on the middle cerebellar peduncle-pons junction adjacent to the mass. We think that including SWI in routine MRI protocol will contribute to the initial diagnosis of acoustic schwannoma and detection of its complications such as subarachnoid hemorrhage and subsequent superficial siderosis.