A 59-year-old female had been treated for epilepsy over 20 years. She had frequent convulsive seizures in spite of medication and was admitted to our hospital in status epilepticus. CT showed low density cyst with calcified wall at right suprasellar region and irregular ring enhancement in the frontal lobe which was continuous with the cyst. Angiography revealed tumor stain in the venous phase. The frontal mass was removed with evacuation of the cyst. Pathological findings were suggestive of squamous cell carcinoma arising from the epithelial component of the pre-existing dermoid cyst. The patient died six months after the operation with severe hyperglycemia, ketoacidosis and hypotension probably due to chemical meningitis and hydrocephalus.