Posterior reversible encephalopathy syndrome mimicking cerebral metastasis: contraindication for biopsy.

The posterior reversible encephalopathy syndrome (PRES) is a well described entity of white matter pathology. PRES is triggered by numerous different factors such as acute elevated arterial hypertension, immunosupressive therapy, chemotherapy, etc. The case of a 67-year old woman is presented. The patient was treated for breast cancer 10 months ago and because of acute disorientation a magnetic resonance imaging (MRI) was performed. In the MRI biparieto-occipital hyperintense lesions were seen. Brain metastases were suspected. After chemotherapy and hypertonia and the typical appearance of the lesions in the MRI, PRES was also suspected. Before initializing the surgery for an open biopsy a follow-up MRI had been performed (2 weeks after initial MRI). In follow-up MRI the lesions disappeared completely proving the diagnosis of PRES. PRES can be misdiagnosed as a tumour and surgery could be mistakenly performed. It's important to keep the differential diagnosis of PRES in mind when radiologic features of the syndrome are present.