Posterior fossa surgery: an unusual cause of superficial siderosis.

With the widespread use of magnetic resonance imaging, an increasing number of cases of superficial siderosis are being discovered. However, the cause remains uncertain in almost half the cases. We report a case where previous surgery for a pontine hematoma established a pathway for extravasation of blood into the 4th ventricle, resulting in superficial siderosis that was demonstrated on a follow-up magnetic resonance imaging scan 8 years later. This case presents an unusual iatrogenic cause of superficial siderosis that has not been reported previously.