Nerve sheath tumor explained

Nerve sheath tumor
Field:	Neuro-oncology

A nerve sheath tumor is a type of tumor of the nervous system (nervous system neoplasm) which is made up primarily of the myelin surrounding nerves. From benign tumors like schwannoma to high grade malignant neoplasms known as malignant peripheral nerve sheath tumors, peripheral nerve sheath tumors include a range of clearly characterized clinicopathologic entities.^[1] A peripheral nerve sheath tumor (PNST) is a nerve sheath tumor in the peripheral nervous system. Benign peripheral nerve sheath tumors include schwannomas and neurofibromas.^[2]

A malignant peripheral nerve sheath tumor (MPNST) is a cancerous peripheral nerve sheath tumor, which are frequently resistant to conventional treatments.^[3]

Origin of peripheral nerve sheath tumors

The primary Schwann cell differentiation and neoplastic proliferations are characteristics of peripheral nerve sheath tumors. For instance, the Schwann cell, which is the major neoplastic cell component of neurofibroma,^[4] is cytologically distinguished by the expression of S-100 protein and wavy nuclear outlines.^{[5] [6]} A variety of peripheral nerve cells, including axons, perineurial cells, fibroblasts, and varying inflammatory components such as mast cells and lymphocytes, are also present in neurofibromas. A population of CD34-positive cells with an unknown histogenesis is also found.^{[7] [8]}

Notes and References

1. Louis, DN.; Ohgaki, H.; Wiestler, OD.; Cavenee, WK., editors. WHO Classification of Tumours of the Central Nervous System. International Agency for Research on Cancer; Lyon: 2007.
2. Web site: Spinal Cord Tumors -- Nerve Sheath Tumors (Schwannomas and Neurofibromas) . . 2007-08-06 .
3. Slomiany MG, Dai L, Bomar PA, Knackstedt TJ, Kranc DA, Tolliver L, Maria BL, Toole BP. Abrogating drug resistance in malignant peripheral nerve sheath tumors by disrupting hyaluronan-CD44 interactions with small hyaluronan oligosaccharides. Cancer Res. 2009; 69:4992–4998. [PubMed: 19470767]
4. Perry A, Roth KA, Banerjee R, Fuller CE, Gutmann DH. NF1 deletions in S-100 protein-positive and negative cells of sporadic and neurofibromatosis 1 (NF1)-associated plexiformneurofibromas and malignant peripheral nerve sheath tumors. Am J Pathol. 2001; 159:57–61. [PubMed: 11438454]
5. Chaubal A, Paetau A, Zoltick P, Miettinen M. CD34 immunoreactivity in nervous system tumors.Acta Neuropathol. 1994; 88:454–458. [PubMed: 7531384]
6. Weiss SW, Langloss JM, Enzinger FM. Value of S-100 protein in the diagnosis of soft tissuetumors with particular reference to benign and malignant Schwann cell tumors. Lab Invest. 1983;49:299–308. [PubMed: 6310227]
7. Carroll S. Molecular mechanisms promoting the pathogenesis of Schwann cell neoplasms. ActaNeuropathol. 2012
8. Weiss SW, Nickoloff BJ. CD-34 is expressed by a distinctive cell population in peripheral nerve,nerve sheath tumors, and related lesions. Am J Surg Pathol. 1993; 17:1039–1045. [PubMed: 7690524]