Third ventricle herniation into the sphenoid sinus following endoscopic transnasal transsphenoidal fenestration of Rathkes cleft cyst.

Rathke cleft cyst (RCC) is an uncommon albeit benign sellar lesion with an incidence rate of between 2 to 33%. RCCs are usually asymptomatic except in the large cases whit suprasellar extension. We herein describe a unique case of RCC, which presented with severe visual loss owing to massive herniation of the optic chiasm and third ventricle down into the sphenoid sinus through a small 8 x 8 mm foramen after transnasal endoscopic surgical fenestration and marsupialization of the cyst. We describe a reconstruction method via endonasal transsphenoidal approach in this case and suggest prophylactic reconstruction of the sellar floor in sellar lesions with equal or more voluminous suprasellar extensions that are susceptible to such massive herniation and secondary empty sella syndrome.