Dorsal midbrain squamous cell carcinoma: Case report and review of literature.

Intracranial epidermoid cyst (EC) is a slow-growing, benign lesion that rarely undergoes a malignant transformation. When it does occur, the clinical course is aggressive. Certain radiological criteria may give a clue to diagnosis and help in deciding the appropriate course of action as well as prognostication. Surgical excision along with adjuvant radiotherapy is the treatment of choice; however, the overall prognosis is poor as complete excision is seldom possible. We present a rare case of malignant transformation of an intracranial EC without previous history of surgery. Subtotal excision of the lesion was possible, with post-operative histopathological examination revealing squamous cell carcinoma. The patient was discharged from the hospital with no fresh deficits. She was, however, re-admitted on day 36 with features of raised intracranial pressure, for which she underwent cerebrospinal fluid diversion. She underwent intensity-modulated radiation therapy later on.