Malignant transformation of residual posterior fossa epidermoid cyst to squamous cell carcinoma.

Malignant transformation of intracranial epidermoid cysts to squamous cell carcinoma is a rare occurrence and only a small number have been reported to date. MRI recurrence in combination with neurological decline should prompt surgery to exclude malignant transformation. Herein, we describe our experience of such a case and contribute to the evolving series within the literature.