They are estimated to account for 5-10% of all soft-tissue sarcomas. They typically present in adults. There is no recognised gender predilection and clinical presentation varies dependant on location.
They can either arise de-novo or de-differentiate from an exising neurofibroma or schwannoma.
Tumours commonly occur close to a plexus of nerve trunk, e.g. sacral plexus/brachial plexus.
- neurofibromatosis type I: in 25-70% of cases
- previous irradiation
Imaging criteria are generally considered unreliable in differentiating from a more benign neurofibroma or schwannoma 4. However general rules favouring a MPNST include:
- the larger the lesion, the more likely for it to be malignant
- irregular borders (although most MPNSTs can have well defined margins)
- rapid growth on interval imaging
- T1: usually isointense to muscle 4; heterogeneous signal on T1 (if present) may useful in differentiating from a neurofibroma 3
- T2: can have low signal due to high collagen content 4
Gallium67 scintigraphy may show higher uptake than that of a neurofibroma 6-7.
Treatment and prognosis
It is an aggressive tumour that carries an extremely poor prognosis.
- 1. Ogose A, Hotta T, Morita T et-al. Diagnosis of peripheral nerve sheath tumors around the pelvis. Jpn. J. Clin. Oncol. 2004;34 (7): 405-13. doi:10.1093/jjco/hyh072 - Pubmed citation
- 2. Lee JH, Lee HK, Choi CG et-al. Malignant peripheral nerve sheath tumor in the parapharyngeal space: tumor spread through the eustachian tube. AJNR Am J Neuroradiol. 2001;22 (4): 748-50. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 3. Wasa J, Nishida Y, Tsukushi S et-al. MRI features in the differentiation of malignant peripheral nerve sheath tumors and neurofibromas. AJR Am J Roentgenol. 2010;194 (6): 1568-74. doi:10.2214/AJR.09.2724 - Pubmed citation
- 4. Rha SE, Byun JY, Jung SE et-al. Neurogenic tumors in the abdomen: tumor types and imaging characteristics. Radiographics. 23 (1): 29-43. doi:10.1148/rg.231025050 - Pubmed citation
- 5. Murphey MD, Smith WS, Smith SE et-al. From the archives of the AFIP. Imaging of musculoskeletal neurogenic tumors: radiologic-pathologic correlation. Radiographics. 19 (5): 1253-80. Radiographics (full text) - Pubmed citation
- 6. Hrehorovich PA, Franke HR, Maximin S et-al. Malignant peripheral nerve sheath tumor. Radiographics. 23 (3): 790-4. doi:10.1148/rg.233025153 - Pubmed citation
- 7. Levine E, Huntrakoon M, Wetzel LH. Malignant nerve-sheath neoplasms in neurofibromatosis: distinction from benign tumors by using imaging techniques. AJR Am J Roentgenol. 1987;149 (5): 1059-64. AJR Am J Roentgenol (abstract) - Pubmed citation