Presentation on theme: "Intramedullary Spinal Cord Lesions in NF1 and NF2"— Presentation transcript:
1 Intramedullary Spinal Cord Lesions in NF1 and NF2 Sheila Kori
2 NF1 Most common neurocutaneous disorder, autosomal dominant Pathophysiology: Mutation in or deletion of the NF1 gene, which encodes neurofibromin, leads to tissue proliferation and tumor development. The oligodendrocyte myelin glycoprotein is embedded in this gene which may be the cause of white matter lesions.Incidence: 1: 3,000-5,000
3 NF1Best Imaging Tool: MRI to evaluate for white matter lesions, visual pathway gliomas, and plexiform lesionsImaging Findings:Hyperintense lesions on T2W1White Matter lesions involve dentate nuclei of cerebellum, globus pallidus, thalamus, pons, midbrain, hippocampusVisual pathway gliomasSphenoid wing dysplasiaAneurysms and moyamoya
4 NF2“MISME”: Multiple intracranial schwannomas, meningiomas, ependymomasPathophysiology: Mutations in the NF2 gene that encodes merlin which functions as a tumor suppressor. Results in decreased function or production of this protein causing development of tumors in the central and peripheral nervous systems. 50% of patients have NF2 as a result of a new gene mutation.Incidence: 1: 40,000
5 NF2 Best Imaging Tool: Contrast enhanced MR Imaging Findings: Bilateral vestibular schwannomasMeningiomas and schwannomas involving CNsSpinal manifestations: meningiomas, ependymomas, and nerve sheath tumors
6 Intramedullary Tumors Intramedullary lesions are rare, 4-10% of CNS tumorsAre found more commonly in patients with neurofibromatosis:NF2 associated with ependymomasNF1 associated with astrocytomasSome reports of intramedullary schwannomas
7 Astrocytomas75% are well-differentiated grade I, 25% are grade III (anaplastic) lesionsUsually eccentrically located within the cord, since it arises from cord parenchyma, infiltrativePoorly defined margins, no cleavage planePatchy enhancement after intravenous contrast material administration.T1WI: Iso- to hypointense relative to the spinal cordT2WI: hyperintenseAverage number of vertebral segments involved = 7
8 AstrocytomasMR T2 (left) and post Gd T1 (right) images show small, cystic, and enhancing astrocytoma.
9 EpendymomasEpendymomas are slow growing, displace adjacent neural tissue, and arise from ependymal cells of central canal causing symmetric cord expansion.T1WI: Iso- or hypointense relative to the spinal cordT2WI: lesions may be isointense or hyperintenseMost cases (60%) show cord edema around the massesAverage number of vertebral segments involved = 3.678%–84% of ependymomas have at least one cyst84% enhanced after administration of intravenous Gd-based contrasts and (89%) had well-defined margins on post Gd imagesNF2 patients with nonsense and frameshift mutations when compared with those of other types of mutations are more likely to have intramedullary tumors but not any other type of tumor.
10 EpendymomasMR T2 (left) and post Gd T1 (right) images show relatively well-defined cervical ependymoma.
11 SchwannomasMost commonly found locations: extradural or intradural extramedullary, however there have been about 60 reports of intramedullary schwannomas.Pathogenesis is unknown. Some theories include:Central inclusion of Schwann cells during embryological developmentAberrant Schwann cells around intramedullary myelin fibersExtension of Schwann cells along the intramedullary perivascular nervous plexusTransformation of pial cells originating from neuroectoderm into Schwann cellsTumoral growth of Schwann cells on a dorsal root located in a critical area corresponding to the point where the dorsal root loses its cover and enters the pia mater
12 Intramedullary Schwannomas Characteristics on MRIWell defined marginsUniform contrast enhancement on post Gd T1WIEccentrically located on axial and coronal imagesTreatment: complete resection, often likely to cure
13 Intramedullary Schwannomas MR sagittal (left) and axial (right) T2 images show well-defined, eccentric schwannoma in mid thoracic spinal cord.
14 ReferencesBarkovich JA. Diagnostic Imaging Pediatric Neuroradiology. 2007; I-8-2 – I-8-9Ozawa N, Tashiro T, et al. Subpial schwannoma of the cervical spinal cord mimicking an intramedullary tumor. Radat Med. 2006; 24:Patronas NJ, Courcoutsakis N, Bromley CM, et al. Intramedullary and spinal canal tumors in patients with neurofibromatosis 2: MR imaging findings and correlation with genotype. Radiology 2001; 218:434Egelhoff JC, Bates DJ, et al. Spinal MR finding in neurofibromatosis Types 1 and 2. AJNR ; 13:Koeller K,Rosenblum, SR, Morrison AL. Neoplasms of the Spinal Cord and Filum Terminale: Radiologic-Pathologic Correlation. RadioGraphics 2000; 20:1721–1749Lee M, Rezai, A, Freed D, Epstein F. Intramedullary Spinal Cord Tumors in Neurofibromatosis. Neurosurgery. 1996; 38:32-37