P08.06CEREBRAL DURAL METASTASES MIMICKING MENINGIOMAS. DIAGNOSTIC AND SURGICAL FEATURES.

Cerebral metastases are the most frequent brain tumors in adults and they are found in 15-30% of patients with a primary tumor. They develop mainly in the brain or cerebellum and less frequently in the meninges. Dural metastases are rare entities and are found in 9% of patients with terminal systemic cancer and in about 5% they represent the only intra-cranial manifestation. However their real incidence is unknown because of the lack of significant numerical series. Clinical presentation with dural-based metastasis mimicking meningioma is very rare and described mostly as case reports from diverse primary locations. The most common primary sites in surgically resected dural metastases have been found to be breast and prostate, but may also be from a primary melanoma, sarcoma, or lymphoma. These often presented as single, cranial and subdural lesions. They can present dural tail sign and often are dural-based or intra-parenchymal. The determination of extra-axial origin of a tumor has a considerable clinical implication. The location of the lesion affects treatment planning and it is predictive for prognosis. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) can show a well defined, lobulated, extra-axial, contrast enhancing lesion. Previously, dural tail sign was reported to be specific for meningiomas, but may be associated with other dural-based lesions. Furthermore, their macroscopic appearance during surgery may even be taken for a meningioma. Because of the prognostic relevance in discriminating both tumors, the definitive diagnosis relies on the histopathological findings. Nowadays MR spectroscopy (MRs) can aid in the differential diagnosis. We report ten cases of dural metastasis from different neoplasms, which on both preoperative CT and MRI and at surgery had the typical appearance of a meningioma. Aim of our study was to investigate the neuroradiological findings and neuropathological aspects of these lesions in order to facilitate the differential diagnosis between meningiomas and other neoplasms. The neuroradiological data were compared with intra-operative characteristics and histological and specific immunohistochemical markers. In our patients the neuroradiological diagnosis of meningiomas was not confirmed by histology. MRs provided interesting complementary data, able to increase the specificity of the neuroradiological diagnosis but in many cases was unconvincing. It is certainly mandatory to resect these lesions, often they have a clear interfaces, much like a meningioma, which allows what appears to be a gross total excision. We still plan to obtain an intra-operative pathologic confirmation for suspected lesions that involve the dura. We also would like to emphasize the precise role of pre-operative diagnosis, which in many cases may be a challenge, to avoid the delay in surgery, with consequent deleterious impact on patient care.