Introduction:
Superficial siderosis of the central nervous system (SS-CNS) is a clinical condition characterized by a pathological accumulation of hemosiderin in the superficial or sub-superficial layer of the central nervous system, causing progressive and irreversible neurological alterations. The most common clinical presentation is characterized by hearing loss, cerebellar dysfunction (with dysarthria and ataxia), and cognitive impairment.

Case report:
We describe the case of a man aged 53 with a sudden worsening of a pre-existing bilateral hearing loss. Clinical examination showed left head tilt, left upper limb paresis, and ataxic gait. A brain CT, US of supra-aortic trunks, and ECG ruled out cardiovascular and focal diseases. The patient was referred to the head-and-neck department for further investigations. Tonal audiometry showed a profound bilateral hearing loss greater on the left at low frequencies with no hearing above 1 kHz. Vestibular examination revealed the absence of nystagmus. The ABR revealed an unstructured trace without sign of any main waves. Transtympanic electrocochleography showed a clear bilateral first wave. A brain MRI revealed hypointensity due to hemosiderin deposition. A lumbar puncture demonstrated abundant red blood cells and xanthochromia, high ferritin, and protein levels in the cerebrospinal fluid.

Conclusions:
From the multidisciplinary evaluation the final diagnosis was superficial siderosis of the central nervous system.