[Two particular cases of superior semicircular canal dehiscence related to a procidence of the superior petrous sinus].

We report two cases of superior semicircular canal dehiscence related to a dehiscence of the superior petrous sinus that creates a localized notch of the most superior part of the superior semicircular canal. This vascular dehiscence was suspected at CT and was confirmed by MR imaging with identification of the superior petrous sinus in touch with the intralabyrinthine fluid at this level. This not well-known etiology of the superior semicircular canal dehiscence syndrome has to be searched and described by radiologists, allowing an optimal surgical approach.