Malignant transformation of a cerebral dermoid cyst into a squamous cell carcinoma with malignant intraperitoneal spreading along a ventriculoperitoneal shunt: illustrative case.

Malignant progression of intracranial dermoid cysts into squamous cell carcinoma is extremely rare with only three reports published so far. Intracranial dermoid cysts are uncommon benign tumors lined by stratified squamous epithelium of embryonic ectodermal origin.