Facial Nerve Schwannoma Presenting as a Mass in the Middle Cranial Fossa: Typical Neuroradiological Patterns for a Preoperative Diagnosis

Facial nerve schwannoma is a rare primary neurogenic tumour that may originate anywhere along the VIIth nerve course. The clinical presentation is highly dependent on the location of the lesion along the nerve course and this makes the pre-operative diagnosis difficult without radiologic examination. The most common presentation is facial palsy and even though tumours are responsible for only 5% of facial palsies, if a patient does not recover within six months a complete work-up for neoplasm is recommended. On the basis of clinical presentation and imaging characteristics radiologists should try to make a preoperative diagnosis, to help in the patient's management and possibly to plan the surgical approach. We describe the case of a successful preoperative diagnosis of facial nerve schwannoma. The aim is to describe the main CT and MRI findings which may help the radiologist to establish a correct differential diagnosis.