Objective: To describe demographic, radiologic, and surgical features in adult patients with spontaneous cerebrospinal fluid otorrhea (SCSFO). STUDIED: Review was made of office and hospital charts of 21 patients with SCSFO and 2 patients with spontaneous CSF rhinorrhea, all of which were repaired successfully from 1989 to 1998.
Method: Radiologic examples of the structure responsible for SCSFO and rhinorrhea are used to illustrate the changes essential for diagnosis.
Results: The responsible lesion for SCSFO and rhinorrhea in the adult are arachnoid granulations (AG) or villi, which do not reach a venous lumen and are aberrantly distributed in areas of the anterior, middle, and posterior cranial fossae that are in proximity to the middle ear/mastoid space, ethmoid, and sphenoid sinuses. The ages of the 21 patients ranged from 38 to 83 years (mean 63 years) with all but one older than 50 years. The sex ratio was 14 women to 7 men; the CSF leak was right sided in 13 and left sided in 8 patients. Eighteen of the SCSF leaks were located in the middle cranial fossa surface of the temporal bone (TB) while two were on the posterior fossa border of the TB. The middle fossa leaks were managed by craniotomy and repair with fascia, whereas the posterior fossa defects were obliterated by adipose tissue inserted through an intact canal wall mastoidectomy. The most common radiologic finding on computerized tomography (CT) was a soft tissue mass adjacent to a tegmen bone defect. The posterior fossa AG created an erosion of cortical and trabecular bone in the mastoid compartment. Spontaneous CSF rhinorrhea in two patients also radiologically appeared as soft tissue mass adjacent to bone erosion in the sphenoid and ethmoid sinuses. These also represent aberrant AGs, which are responsible for CSF rhinorrhea in later life.
Conclusions: The demographic, radiologic, and pathologic findings in this series of 21 TB and 2 paranasal sinus SCSF leaks support the concept that the responsible lesions are AGs that are aberrantly located adjacent to pneumatized parts of the skull. Because these AGs enlarge with age, they may erode through the bony confines of the TB and sinuses and present as SCSFO or rhinorrhea in middle and old age.