[Superficial siderosis of the central nervous system: a case report].

Superficial siderosis of the central nervous system is secondary to chronic subarachnoid bleeding. However, the underlying etiology is not always detected. Superficial siderosis can be diagnosed at MRI by the presence of a hypointense rim along the brain surface on gradient echo T2W images. The authors report a case of superficial cerebral siderosis where the underlying etiology remained undiagnosed in spite of extensive neuroradiological work up.