[Malignant degeneration in a parapontine epidermoid (author's transl)].

A case of malignant degeneration in a right parapontine epidermoid cyst giving rise to leptomeningeal carcinomatosis in a 57 year old woman is presented. The malignant tissue had infiltrated the right cerebellar hemisphere and produced a symptomatic trigeminal neuralgia, a change in the psychological state of the patient, and an acute conus and cauda syndrome following metastasis implantation. Only eight unequivocal previous reports of malignant transformation of intracranial epidermoid cyst have been reported in the literature with metastases in four.