This is a 67-year old male patient who presented with chronic
ataxia.
Diagnosis
Superficial Siderosis
Findings
Image #1: T1W axial images show no abnormality. Image #2, #3: T2W
axial images show dark signal coating pons, brainstem and spinal
cord. Image #4: T2W sag images show dark signal coating brainstem
and entire spinal cord.
Discussion
This abnormality is a rare disorder which is characterized by the
deposition of hemosiderin on the leptomeninges of the cerebrum,
cerebellum, brainstem, spinal cord, and cranial nerves. Chronic
subarachnoid hemorrhage is believed to be the cause of the
hemosiderin deposition. Source of hemorrhage can be from such
entities as AVM's, however, sometimes no source is found as was the
case in this patient (despite the MRI and a cerebral angiogram).
The acoustic nerve is especially susceptible to the toxic effect of
hemosiderin deposition due to its long course. These patients
present usually with sensorineural hearing loss and/or ataxia. This
patient presented with ataxia. Patients will have hemorrhagic or
xanthochromic CSF. There is no differential diagnosis for this
abnormality. Reference(s): Head & Neck Imaging - 3rd edition,
Som and Curtin,