Background: A 15-year-old girl presented in a Dutch hospital with right-sided trigeminal neuralgia. MR-imaging showed a mass lesion in the right cavernous sinus. Differential diagnosis in this hospital was a meningioma or a schwannoma. The patient was referred to the neurosurgery department of our hospital, and resection of the lesion was planned. At surgery, the lesion presented as a subdural bulge surrounded by swollen venous structures. The incision of the dura resulted in profuse hemorrhage of arterial origin, and hemostasis was obtained with difficulty. The tumor showed a fibrillar structure and a strong arterial vascularization which was not concordant with schwannoma. No further exploration of the lesion was performed, and no biopsy was obtained. To clarify the unexpected surgical findings and to reach a diagnosis without biopsy , pre-operative MR-images were reviewed. Digital subtraction angio graphy (DSA) was performed postoperatively. The lesion did not take up FDG on PET scan. Laboratory results showed increased catecholamines in the urine