Introduction: To present a complex case of giant MENINGOENCEPHALOCELE after a canal wall down mastoidectomy and describe our preferred approach to repair meningoencephalic herniation of the temporal bone. Case Report: A 20-year-old patient, who had previously undergone type III tympanoplasty with total ossicular reconstruction prosthesis for an attic cholesteatoma, presents with clinical and imaging features compatible with the diagnosis of a giant temporal MENINGOENCEPHALOCELE. We performed a combined approach –, transmastoid plus minicraniotomy-to repair the skull base defect. A multilayer reconstruction of the defect with septal cartilage and temporal fascia was performed. After a 48 months follow-up, the patient remains symptom free without signs of tissue herniation. Conclusions: Transmastoid plus minicraniotomy combined approach is a safe and feasible technique in case of large and anterior skull base defects with low surgical morbidity, allowing a safe and multilayered reconstruction, even in the context of a simultaneous active chronic otitis media.

Congenital skull base MENINGOENCEPHALOCELEs (MECs) are exceedingly rare lesions, occurring in approximately 1/35000 live births. Basal encephaloceles include spheno-orbital, sphenoethmoidal, sphenomaxillary, transethmoidal, and transsphenoidal lesions. Among them, the transsphenoid MENINGOENCEPHALOCELE (TSME) are the rarest, occurring in 1/700000 live births. . .