[Secondary malignant tumors of the vestibulocochlear and facial nerves]

Neuromas and meningiomas represent by far the most frequent tumors of the cerebellopontine cistern (respectively over 80% and over 10%). Secondary malignant tumors are exceptional.Presentation of four cases of malignant tumors of the cerebellopontine cistern, either revealing or complicating a primary tumor: a bronchial cancer, a cancer of the kidney, a medulloblastoma and a lymphoma. Patients were studied in T2- and T1-weighted high-field MRI sequences before and after gadolinium injection.The four tumors were enhanced by gadolinium and shown to invade the internal auditory canal, including one bilateral involvement. In most cases, the tumors were slightly heterogeneous and had irregular margins.These observations suggest that other diagnoses than acoustic neuroma should be taken into account.