Primary intracranial squamous cell carcinoma arising in an epidermoid cyst—A case report and review of literature

Primary intracranial squamous cell carcinoma is extremely rare, with most of the cases arising from malignant transformation of an epidermoid or a dermoid cyst. We report here a case of a 45-year-old male patient who presented with 1-month history of intermittent headache and recent onset of altered sensorium. Imaging revealed a midline posterior fossa mass lesion compressing the fourth ventricle and causing hydrocephalus. A provisional diagnosis of dermoid cyst was considered. Histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity.