Primary diffuse leptomeningeal gliosarcomatosis with a sphenoid/sellar mass: confirmation of the ectopic glial tissue theory?

Gliosarcoma is a rare glioblastoma variant, classically arising in the cerebral hemispheres. We report a patient with primary diffuse leptomeningeal gliomatosis (PDLG) with a sphenoid sinus and sellar mass. An 84-year-old woman presented with progressive headache and right-sided visual failure, associated with ipsilateral oculomotor nerve palsy and left temporal field loss. Neuraxial MRI showed a large lesion within the sphenoid sinus and sella resulting in chiasmal compression, and diffuse cranial and spinal leptomeningeal enhancement. Endoscopic transphenoidal biopsy and debulking of the sphenosellar lesion was performed, and gliosarcoma was diagnosed on histopathological examination. The patient was palliated due to poor performance status. To our knowledge, this is the only report of gliosarcoma within the paranasal sinuses and the second report of PDLG where the histological analysis has confirmed gliosarcoma. We believe this adds significant weight to the theory that heterotopic nests of glial tissue, in this instance within the sphenoid or sella, are the putative origin of PDLG.