Meningiomas of the transverse--sigmoid sinus junction area.

Meningiomas with exclusive or prevalent dural attachment over the transverse-sigmoid sinus junction area represent a well-defined subgroup of posterior fossa meningiomas. This study reports 13 cases of this localisation (10.8% of all infratentorial meningiomas). In this series, six patients (46%) were discovered as an incidental MR finding. One patient with a small (1.5 cm) meningioma presented with an intracranial hypertension syndrome due to severe obstruction of the unique transverse-sigmoid sinus junction. A MR angiography was performed in 11 patients; it showed intraluminal tumour in two cases with dominant and unique transverse sinus, respectively. Tumour removal with excision of the outer dural layer and coagulation of the dural attachment (Simpson II) was performed in 11 cases; in two others with focal sinus invasion, removal of the small intravenous tumour fragment was not performed (Simpson III). No post-operative complications occurred. Remission of pre-operative symptoms was obtained in all symptomatic cases. The management of the transverse-sigmoid sinus junction is the main problem of meningiomas of this region. Excision of the outer dural layer and coagulation of the dural attachment are in our opinion sufficient in most cases, even when there is tumour invasion of the patent venous lumen. The resection of the sinus wall should be reserved to cases with a totally obstructed segment and symmetrical or asymmetrical but present transverse and sigmoid sinuses.