We present the case of a 36-year old woman who was referred to our hospital with an 8 weeks history of walking difficulties, nausea and vomiting, diminished hearing on the right side and diplopia. On Magnetic Resonance-Imaging (MRI) a tumour in the right cerebellopontine angle (CPA) was diagnosed. The tumour was resected and histopathological examination revealed an adenocarcinoma, suspicious for a metastasis from carcinoma of the breast considering the aspect of the cells, immunochemical profile, age and gender of the patient. No primary tumour was found. In cases without histopathological diagnosis, radiosurgery should be withheld when there is doubt about the clinical or radiological diagnosis.