[Spontaneous rhinorrhea due to (congenital?) evagination of arachnoidea in the paranasal sinuses].

Report on two cases of spontaneous, intermittent and long lasting spinal fluid rhinorrhea. The lesion responsible of the spinal fluid fistula is a glio-arachnoid expansion of the convexity of the frontal pole, contained into a fibrous pedicle ; it crosses the dura mater and penetrates, through a well individualized bone orifice, into the posterior wall of the frontal sinus or into an ethmoid-frontal cell. This arachnoid diverticle is not associated with an hydrocephalon. In the absence of any traumatic past history, its congenital nature may be admitted. No para-clinical investigation makes possible to detect such a minor abnormity ; the isotopic transit of the spinal fluid may remain silent, when performed at a moment of drying up of the nasal flow. Surgical exploratory study of the anterior level has to be complete, while numerous independent diverticles may coexist.