Transsphenoidal meningoencephalocele protruding into the nasal cavity

Abstract

Spontaneous transsphenoidal meningoencephalcele is a rare entity, even rarer through the Sternberg’s canal, a congenital defect on the lateral wall of the sphenoid sinus. We report such a case in an obese 52-year-old female with spontaneous cerebrospinal fluid (CSF) rhinorrhoea and recurrent meningitis. Brain CT, MRI and CT cisternography were performed. Surgical correction and short-term follow-up were recorded. CT scan showed a defect on the lateral wall of the right sphenoid sinus filled with a soft tissue mass extending to the nasal cavity. MRI scan revealed brain parenchyma from the right temporal lobe herniated through the sphenoid bone defect. CT cisternography showed 270 mmH2O opening pressure and confirmed the CSF leakage. Surgical correction was performed with resolution of the symptoms. MRI and CT are complementary modalities for evaluating this entity, the first being the method of choice for meningoencephalcele diagnosis although bone defects are best depicted on CT scan. CT cisternography identifies the specific site of leak and confirms benign intracranial hypertension, consistently reported in meningoencephaloceles. Obesity and benign intracranial hypertension have been reported as a combined mechanism allegedly contributing to meningoencephaloceles through congenital skull base defects, by increasing intraabdominal pressure thus decreasing venous return, with augmented intracranial pressure and subsequent reduced absorption of the CSF.

Meningoencephalocele in the Lateral Sphenoid Sinus Showing Malformation of Cortical Development: A Case Report

“…4) As a physiologic factor of meningoencephalocele in the lateral SS, progressive erosion of the skull base in patients with IICP and well-pneumatized sphenoid sinuses may result in focal areas of dehiscence and herniation of the brain parenchyma. 5) Generally, whether CSF pressure is increased in patients with unruptured brain AVMs, as in our case, remains to be unclear. Rossitti reported a theory for the pathophysiologic development of increased CSF pressure in patients with brain AVMs and applied a basic hydraulic hypothesis related to cerebral intravascular and CSF pressures.…”

“…Spontaneous meningoencephalocele in the lateral SS is considered rare, and it is often accompanied by various clinical symptoms, such as cerebrospinal fluid (CSF) rhinorrhea, chronic headache, epileptic seizures, and meningitis. [2][3][4][5] Surgical repair of the skull base is often attempted to prevent central nervous system infection in patients with CSF rhinorrhea. Previously, the etiopathogenesis of meningoencephalocele in the lateral SS was believed to be correlated with a persistent skull base bone defect in the lateral craniopharyngeal (Sternberg's) canal.…”

Camurati-Engelmann disease combined with transethmoidal meningoencephalocele: illustrative case

“…In general, chronic intracranial hypertension leads to thinning of the cranial sutures between the temporal bone, sphenoid bone, and cribriform plate, inducing herniation of the brain tissue via such cranial bones. [9][10][11] As a result, meningoencephalocele develops in the anterior skull base. [9][10][11] The cranial vault and the anterior skull base are essentially formed by intramembranous ossification and endochondral ossification, respectively.…”

“…[9][10][11] As a result, meningoencephalocele develops in the anterior skull base. [9][10][11] The cranial vault and the anterior skull base are essentially formed by intramembranous ossification and endochondral ossification, respectively. 12 In CED, only the former is hypertrophic, inducing chronic intracranial hypertension.…”

True Transsphenoidal Meningoencephalocele

“…Sphenoid meningoencephaloceles may be congenital, traumatic, surgical, or due to intracranial hypertension. [1][2][3] Symptoms include recurrent bacterial meningitis, symptomatic intracranial hypotension, CSF rhinorrhea, or paranasal sinus obstruction. There are 2 types of transsphenoidal encephalocele: intrasphenoidal and true transsphenoidal.…”