Endoscopic assisted minimally invasive resection of petrous bone epidermoid cyst via a presigmoid burr hole approach: illustrative case.

backgroundIntracranial epidermoid cysts are rare congenital lesions accounting for approximately 1% of intracranial tumors. Petrous apex involvement is uncommon and surgically challenging because of the lesion's proximity to critical neurovascular structures. Reports describing minimally invasive endoscope-assisted approaches in this location remain limited. OBSERVATIONS: A 32-year-old man presented with progressive right-sided otalgia, pulsatile tinnitus, and hearing loss. Imaging demonstrated a destructive petrous temporal bone lesion with atypical diffusion characteristics, initially suspected to represent a jugular foramen tumor. The patient underwent a minimally invasive endoscope-assisted presigmoid burr hole approach. Intraoperatively, the lesion demonstrated the characteristic pearly appearance of an epidermoid cyst and was resected piecemeal under microscopic and endoscopic visualization. Endoscopic assistance improved visualization of deep and angled extensions beyond the microscopic field. Postoperatively, the patient had preserved facial nerve function, stable hearing, and an uneventful recovery. Histopathological examination confirmed an epidermoid cyst. LESSONS: Petrous apex epidermoid cysts require balancing maximal safe resection with preservation of neurological function. This case highlights the potential utility of a minimally invasive endoscope-assisted approach for improving visualization within constrained skull base corridors while minimizing operative morbidity. Long-term radiological surveillance remains important when complete capsule removal is not safely feasible. https://thejns.org/doi/10.3171/CASE26361.