Venous stroke can be the unusual clinical presentation of an arising naso-ethmoidal encephalo-meningocele in adulthood.

Trans-ethmoidal encephalo-meningocele is an extremely rare event among the adult population. It mainly affects young people who have previously reported a head injury. Even though early treatment is mandatory to avoid septic complications, the diagnosis is usually late because of the misleading symptomatology. We describe the unusual clinical history of an adult patient with a giant trans-ethmoidal encephalo-meningocele. A 61-year-old woman presented progressively more intense headache and rhinorrhea. No trauma was reported. We learned that she had a history of misunderstood spontaneous rhinorrhea beginning two years before, followed one year later by a lateral sinus thrombosis which worsened the cerebrospinal fluid leakage. Some months after stroke a new cerebral magnetic resonance scan revealed a giant trans-ethmoidal encephalo-meningocele. The brain herniation was surgically removed by a subfrontal intradural approach through a frontal craniotomy. Even rare, giant naso-ethmoidal encephalo-meningocele has to be considered in adult patients presenting with rhinorrhea even without a history of meningitis or neurological defects. Venous stroke can affect patients in whom prolonged CSF leakage occurs because of misunderstood cerebrospinal fistula. These patients must be monitored after stroke for the possible onset of an encephalo-meningocele.