LAUSR

• Arachnoid cyst of the fallopian canal should be suspected and sought in all cases of CSF leak or bacterial meningitis (especially Streptococcus pneumonia, Haemophilus influenzae) in overweight middleaged women without any osteo-meningeal breach identified on the tegmen tympani. • A combination of CT scan and MRI allows the diagnosis of arachnoid cyst of the fallopian canal, can be used to rule out other confounding diagnoses and provides all essential preoperative information. • No systematic surgery is needed for arachnoid cysts of the fallopian canal that have no CSF leak. • When a leak from an arachnoid cyst is identified or when it is associated with a history of meningitis, surgery is needed; a middle ear approach allows minimal invasion with good long-term results. • The idiopathic intracranial hypertension syndrome should be sought in cases of arachnoid cyst of the fallopian canal by performing ophthalmological examination and cerebral MRI. References