Table of Contents
Definition / general | Terminology | Sites | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Cytology description | Cytology images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Kresak JL, Yachnis AT. Solitary fibrous tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumorhpc.html. Accessed March 28th, 2023.
Definition / general
- Grade II or III of IV
- Most are grade II
- Criteria for grade III include > 5 mitoses/10 HPF with "moderate to high" nuclear atypia and "moderate to high" cellularity
- < 1% of all primary CNS tumors
- 60% men, mean age 45 years
- Usually single mass attached to meninges of brain or spinal cord (resembles meningioma radiographically)
- Recently reported overall survival (OS) 84 months, 5 year survival 94% and 10 year survival 72%, (World Neurosurg 2014;81:556)
- 41% recur, 12 - 20% metastasize to extra or intracranial sites (World Neurosurg 2014;81:556)
- May invade through neighboring bone
Terminology
- Hemangiopericytoma is still current terminology in the CNS and is a distinct neuropathologic entity (not lumped together with solitary fibrous tumor)
- Formerly called angioblastic meningioma
Sites
- Dural based
- Often supratentorial
- 10% spinal
Radiology description
- Often homogenously enhancing and well demarcated from adjacent brain - resembles meningioma
Radiology images
Prognostic factors
- Grade III associated with worse overall survival
- No statistical significance between grades II and III in regards to metastatic potential or local recurrence (J Clin Neurosci 2014;21:1310)
Case reports
- 16 year old boy with intradural extramedullary hemangiopericytoma of dorsal spine (Childs Nerv Syst 2015;31:173)
- 41 year old woman with meningeal tumor (University of Pittsburgh: Dura Based Occipital Mass [Accessed 1 August 2018])
- 47 year old quadriplegic woman with recurrent paraspinal tumor (Arch Pathol Lab Med 2002;126:987)
- 47 year old woman with tumor of hypoglossal nerve (AJNR Am J Neuroradiol 2003;24:343)
- 52 year old woman with pleural mass (Arch Pathol Lab Med 2004;128:1061)
- 59 year old man with hemangiopericytoma of the posterior fossa (Brain Tumor Res Treat 2013;1:95)
- 61 year old woman with malignant tumor (University of Pittsburgh: Brain Pathology Case of the Month [Accessed 1 August 2018])
- 67 year old man with tumor at spinal nerve root (Arch Pathol Lab Med 2004;128:335)
Treatment
- Gross total resection
- Sometimes embolization prior to resection
- Postoperative radiotherapy (Neurosurgery 2013;73:624)
- Radiosurgery, an option for treatment of recurrence (J Clin Neurosci 2011;18:1500)
Gross description
- Dural based, gray to red
- May be well circumscribed from brain parenchyma
- Size can vary widely
Microscopic (histologic) description
- Sheets of cells with uniform hypercellularity, cells are homogeneous with moderate amount of cytoplasm, round to oval nuclei and moderate pleomorphism
- Monomorphous cellular spindle cell tumor with round to oval nuclei
- Intratumoral staghorn vessels
- May have storiform pattern
Cytology description
- Cohesive clusters, does not squash well
- Individual cells, when present, are round to ovoid "naked nuclei"
Positive stains
- Vimentin
- Pericellular reticulin pattern
- STAT6 (Acta Neuropathol 2013;125:651)
- CD99
- CD34 (may be patchy or absent)
Electron microscopy description
- Extensive basement membrane around every cell
- Small bundles of intermediate filaments
- No desmosomes
- No gap junctions
Differential diagnosis
- Anaplastic meningioma: chromosomal deletions, strong EMA+, weak / negative BCL2 and CD99 (Hum Pathol 2004;35:1413)
- Fibrous meningioma: 80% EMA+, 80% S100+
- Glioma
- Meningioma: EMA+, PR+, whorls, psammoma bodies, etc.
- Metastasis
- Solitary fibrous tumor: CD34+, CD99+
Additional references