Giant epidermoid cyst penetrating the skull: a case report and literature review.

Intracranial epidermoid cyst is a rare pseudotumor of the nervous system, accounting for 0.2%-1.8% of all intracranial tumors. It is usually located in the cerebellopontine Angle or parasellar area, with insipid onset, slow growth and usually less than 2 cm in diameter. Giant epidermoid cysts that invade the bone have rarely been reported in the literature. Herein, we report a case of giant ECs extradural to the parietal bone, penetrating the skull and continuing to expand outward. In addition, a systematic search of four authoritative databases was conducted to collect the relevant reports of giant epidermoid cyst with diameter > 5cm for the first time, and to discuss the clinical and radiographic features of patients with giant epidermoid cyst and the influence of treatment options.