CLINICAL ARTICLE Solitary fibrous tumors of the central nervous system: report of five cases with unusual clinicopathological and outcome patterns François Vassal & Romain Manet & Fabien Forest & Jean Phillipe Camdessanche & Michel Péoc’h & Christophe Nuti Received: 8 July 2010 / Accepted: 30 October 2010 / Published online: 10 November 2010 # Springer-Verlag 2010 Abstract Background This is a retrospective study of 11 patients harboring a solitary fibrous tumor (SFT) of the central nervous system (CNS), with special emphasis on unusual clinicopathological and outcomes patterns. Method Between 2000 and 2008, 11 patients harboring CNS SFTs were treated at our institution. Patient charts were retrospectively reviewed and tumor location, clinical presentation, imaging characteristics, extent of resection, dural origin, pathological features, adjuvant treatment, and follow-up data were collected, focusing on five atypical cases (four intracranial and one within the spine). Findings One intracranial SFT arose from the sella turcica and relapsed threefold during the 6 years following partial removal. Disease progressed as successive isolated local recurrences treated by subsequent surgical interventions and gamma-knife radiosurgery. The MiB-1 labeling index analysis showed a steady increase in these sequential recurrences (ranging from less than 3% up to 6%) without obvious malignant transformation. The second SFT oc- curred in the cerebellopontine angle and exhibited a high MiB-1 index (10%) without noticeable features of malig- nancy. It relapsed twice during the 5 years following gross total resection without demonstrating a more aggressive histological pattern. The third SFT arose from the cerebellar tentorium, widely invaded the lateral sinus and adjacent bone, had a low MiB-1 index, and has not recurred within the 2 years after incomplete resection. The two remaining SFTs presented with unusual clinicoradiological features. We described a extremely rare case of intraventricular SFT, and a case of extradural SFT of the thoracic spine (T8–T9) radiologically consistent with a schwannoma. Immunohis- tochemistry confirmed that all tumors were SFTs. Conclusions These atypical presentations gave us the opportunity to provide further information about the variability of the clinicoradiological patterns and natural histological course of CNS SFTs. Keywords Central nervous system tumors . Solitary fibrous tumor . Lateral ventricle . Sella turcica . Spinal cord . CD34 . Biological potential Abbreviations CNS Central nervous system CPA Cerebellopontine angle CT Computed tomography EMA Epithelial membrane antigen GKRS Gamma-knife radiosurgey GTR Gross total removal HPC Hemangiopericytoma HPF High-power fields F. Vassal : R. Manet : C. Nuti Department of Neurosurgery, North Hospital, University Hospital of Saint-Etienne, Saint-Etienne, France F. Forest : M. Péoc’h Department of Pathology, North Hospital, University Hospital of Saint-Etienne, Saint-Etienne, France J. P. Camdessanche Department of Neurology, North Hospital, University Hospital of Saint-Etienne, Saint-Etienne, France F. Vassal (*) Service de Neurochirurgie, Hôpital Nord, Avenue Albert Raimond, 42270, Saint-Priest en Jarez, France e-mail: francoisvassal@wanadoo.fr Acta Neurochir (2011) 153:377–384 DOI 10.1007/s00701-010-0866-4