Idiopathic diffuse erosion of the skull base presenting as cerebrospinal fluid rhinorrhoea

We present an unusual case of generalized erosion of the skull base. We have not found a similar case reported in the world literature. The presenting symptom was spontaneous cerebrospinal fluid (CSF) rhinorrhoea which arose from a bony defect associated with herniation of the right temporal lobe into the sphenoid sinus. We discuss the management of such a case including imaging of the skull base and the endoscopic repair of the bony defect.