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Cranial Nerve V3 Schwannoma - Radiology

last modified on: Fri, 11/10/2023 - 10:33

  • Also known as neurilemmoma or neurinoma of cranial nerve V3 (Agrawal et al. 2017)

  • A benign peripheral nerve sheath tumor which leads to displacement of CN V3 fascicles and frequently transverses the skull base via the foramen ovale (Agrawal et al. 2017)

  • Most common along the proximal portion of the nerve

  • May rarely involve the branches of CN V3 such as the inferior alveolar or mental nerves

  • Involvement of CN V3 branches may result in atrophy of the anterior bellies of the digastric and the mylohyoid

  • Associated with neurofibromatosis type II (Skolnick et al. 2016)

  • Patients may experience pain or neurological symptoms due to mass effect (Agrawal et al. 2017)

  • On CT:

    • Non-contrast: iso- to hypodense compared to muscle; look for enlargement of the mandibular foramen or foramen ovale, muscles of mastication atrophy

    • Contrast: Mild to moderate enhancement of the lesion, larger lesions may show heterogeneous enhancement

  • On MR:

    • T1: iso- to hypointense compared to muscle; hemorrhage may be bright; fatty infiltration of mucles of mastication

    • T2: iso- to hyperintense with bright muscle atrophy via V3 denervation

    • T1 post-contrast: cystic changes may be observed as rim-enhancing inclusions, moderately enhancing

References

Agrawal A, Singh V, Bhagol A, Kumar P, Narwal A. Extracranial Trigeminal Schwannomas: A Retrospective Analysis. J Maxillofac Oral Surg. 2017 Jun;16(2):164-169. doi: 10.1007/s12663-016-0939-x. Epub 2016 Jul 11. PMID: 28439155; PMCID: PMC5385681.

Başak H, Mulazimoglu S, Yucel L, Beton S, Meco C. Purely Endonasal Endoscopic Approaches for Extracranial Trigeminal Nerve Schwannoma. J Craniofac Surg. 2022 Nov-Dec 01;33(8):2473-2476. doi: 10.1097/SCS.0000000000008687. Epub 2022 Jun 29. PMID: 35765130.

Davis DD, Kane SM. Neurilemmoma. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560827/

Skolnik AD, Loevner LA, Sampathu DM, Newman JG, Lee JY, Bagley LJ, Learned KO. Cranial Nerve Schwannomas: Diagnostic Imaging Approach. Radiographics. 2016 Sep-Oct;36(5):1463-77. doi: 10.1148/rg.2016150199. Epub 2016 Aug 19. PMID: 27541436.