Schwannomas are homogeneous tumors, consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow-growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant, degenerating into a form of cancer known as neurofibrosarcoma. These masses are generally contained within a capsule, so surgical removal is often successful.[3]
Schwannomas can be associated with neurofibromatosis type II, which may be due to a loss-of-function mutation in the protein merlin.[4] They are universally S-100 positive, which is a marker for cells of neural crest cell origin.
Schwannomas of the head and neck are a fairly common occurrence and can be found incidentally in 3–4% of patients at autopsy.[4] Most common of these is a vestibular schwannoma, a tumor of the vestibulocochlear nerve that may lead to tinnitus and hearing loss on the affected side. Outside the cranial nerves, schwannomas may present on the flexor surfaces of the limbs. Rare occurrences of these tumors in the penis have been documented in the literature.[5]
Pleural schwannoma is extremely rare. A unique subtype of schwannoma that typically develops in superficial (cutaneous or subcutaneous) sites and may be identified by its development pattern, which is plexiform (intraneuralnodular).[6][7] The correlation with schwannoma predisposition disorders like NF2 and schwannomatosis, however, is minimal (approximately 5 percent of cases).[8] These tumors might lack a capsule or be less encapsulated than a typical schwannoma.More challenging to identify from MPNST are the infrequent plexiform schwannomas that develop in deep anatomical sites, such as soft tissue[9] or major peripheral nerves.[10] These tumors may exhibit enhanced cellularity and mitotic activity. Although the likelihood of these tumors developing into cancer is extremely low, local recurrence is possible in around half of cases. On MRI, it usually shows hyper or iso-intensity on T1-weighted images and heterogenous hyperintensities on T2 weighted images. Pleural schwannoma typically shows fatty degeneration, hemorrhage, perivascular hyalinization, and cystic formation thus giving heterogenous hyperintensities on T2 weighted images. Complete surgical removal of pleural schwannoma is the usual treatment.[11]
Cellular schwannoma is a relatively rare variation. Cellular schwannoma is nearly exclusively made up of a fascicular proliferation of well-differentiated Schwann cells that are cytologically bland, missing Verocay bodies, and just slightly exhibiting Antoni B pattern growth (10% of the tumor area).[12][13][14] Local recurrence is Variable (5-40%) and perhaps greater than in normal schwannomas.[15][16]
Melanotic schwannoma is an uncommon, unique, and possibly cancerous neoplasm defined by epithelioid cells with variable-sized nuclei, substantial melanin deposition in neoplastic cells, and associated melanophages.[17]
Galleryedit
Subcutaneous schwannoma
Antoni A area of schwannoma with Verocay bodies (one annotated by circle)
^Biswas D, Marnane CN, Mal R, Baldwin D (September 2007). "Extracranial head and neck schwannomas--a 10-year review". Auris, Nasus, Larynx. 34 (3): 353–359. doi:10.1016/j.anl.2007.01.006. PMID 17376620.
^ abHanemann CO, Evans DG (December 2006). "News on the genetics, epidemiology, medical care and translational research of Schwannomas". Journal of Neurology. 253 (12): 1533–1541. doi:10.1007/s00415-006-0347-0. PMID 17219030. S2CID 11854280.
^Nguyen AH, Smith ML, Maranda EL, Punnen S (June 2016). "Clinical Features and Treatment of Penile Schwannoma: A Systematic Review". Clinical Genitourinary Cancer. 14 (3): 198–202. doi:10.1016/j.clgc.2015.12.018. PMID 26797586.
^Fletcher CD, Davies SE. Benign plexiform (multinodular) schwannoma: a rare tumour unassociated with neurofibromatosis. Histopathology. 1986; 10:971–980. [PubMed: 3096870]
^Woodruff JM, Marshall ML, Godwin TA, Funkhouser JW, Thompson NJ, Erlandson RA. Plexiform (multinodular) schwannoma. A tumor simulating the plexiform neurofibroma. Am J Surg Pathol. 1983; 7:691–697. [PubMed: 6638259]
^Berg JC, Scheithauer BW, Spinner RJ, Allen CM, Koutlas IG. Plexiform schwannoma: a clinicopathologic overview with emphasis on the head and neck region. Hum Pathol. 2008; 39:633–640. [PubMed: 18439936]
^Agaram, N. P.; Prakash, S.; Antonescu, C. R.; "Deep-seated plexiform schwannoma: a pathologic study of 16 cases and comparative analysis with the superficial variety", American Journal of Clinical Pathology, 29:1042–1048, 2005 [PubMed: 16006798]
^Hebert-Blouin MN, Amrami KK, Scheithauer BW, Spinner RJ. Multinodular/plexiform (multifascicular) schwannomas of major peripheral nerves: an underrecognized part of the spectrum of schwannomas. J Neurosurg. 2010; 112:372–382. [PubMed: 19499977]
^Iwasaki T (2016). "Giant ancient schwannoma of the pleura: Commentary". Lung India. 33 (4): 449–50. doi:10.4103/0970-2113.184928. PMC4948239. PMID 27578944.
^Casadei GP, Scheithauer BW, Hirose T, Manfrini M, Van Houton C, Wood MB. Cellular schwannoma. A clinicopathologic, DNA flow cytometric, and proliferation marker study of 70 patients. Cancer. 1995; 75:1109–1119. [PubMed: 7850709]
^Fletcher CD, Davies SE, McKee PH. Cellular schwannoma: a distinct pseudosarcomatous entity. Histopathology. 1987; 11:21–35. [PubMed: 3557324]
^Wick, M. R.; Swanson, P. E.; Scheithauer, B. W.; Manivel, J. C.; "Malignant peripheral nerve sheath tumor: An immunohistochemical study of 62 cases", American Journal of Clinical Pathology, 87:425–433, 1987 [PubMed:2435144]
^White W, Shiu MH, Rosenblum MK, Erlandson RA, Woodruff JM. Cellular schwannoma. A clinicopathologic study of 57 patients and 58 tumors. Cancer. 1990; 66:1266–1275. [PubMed:2400975]
^Casadei GP, Scheithauer BW, Hirose T, Manfrini M, Van Houton C, Wood MB. Cellular schwannoma. A clinicopathologic, DNA flow cytometric, and proliferation marker study of 70 patients. Cancer. 1995; 75:1109–1119. [PubMed: 7850709]
^Mennemeyer, R. P.; Hallman, K. O.; Hammar, S. P.; Raisis, J. E.; Tytus, J. S.; Bockus, D.; "Melanotic schwannoma: Clinical and ultrastructural studies of three cases with evidence of intracellular melanin synthesis", American Journal of Clinical Pathology, 3:3–10, 1979 [PubMed: 534381]
External linksedit
December 20, 2023
schwannoma, schwannoma, neurilemmoma, usually, benign, nerve, sheath, tumor, composed, schwann, cells, which, normally, produce, insulating, myelin, sheath, covering, peripheral, nerves, other, namesneurilemoma, neuroma, neurolemoma, schwann, cell, tumor, micr. A schwannoma or neurilemmoma is a usually benign nerve sheath tumor composed of Schwann cells which normally produce the insulating myelin sheath covering peripheral nerves SchwannomaOther namesneurilemoma 1 621 neuroma 2 neurolemoma 2 Schwann cell tumor 2 Micrograph of a schwannoma showing both a cellular Antoni A area top and a loose paucicellular Antoni B area bottom HE stain SpecialtyNeuro oncologySchwannomas are homogeneous tumors consisting only of Schwann cells The tumor cells always stay on the outside of the nerve but the tumor itself may either push the nerve aside and or up against a bony structure thereby possibly causing damage Schwannomas are relatively slow growing For reasons not yet understood schwannomas are mostly benign and less than 1 become malignant degenerating into a form of cancer known as neurofibrosarcoma These masses are generally contained within a capsule so surgical removal is often successful 3 Schwannomas can be associated with neurofibromatosis type II which may be due to a loss of function mutation in the protein merlin 4 They are universally S 100 positive which is a marker for cells of neural crest cell origin Schwannomas of the head and neck are a fairly common occurrence and can be found incidentally in 3 4 of patients at autopsy 4 Most common of these is a vestibular schwannoma a tumor of the vestibulocochlear nerve that may lead to tinnitus and hearing loss on the affected side Outside the cranial nerves schwannomas may present on the flexor surfaces of the limbs Rare occurrences of these tumors in the penis have been documented in the literature 5 Verocay bodies are seen histologically in schwannomas Contents 1 Variants 2 Gallery 3 See also 4 References 5 External linksVariants editPleural schwannoma is extremely rare A unique subtype of schwannoma that typically develops in superficial cutaneous or subcutaneous sites and may be identified by its development pattern which is plexiform intraneuralnodular 6 7 The correlation with schwannoma predisposition disorders like NF2 and schwannomatosis however is minimal approximately 5 percent of cases 8 These tumors might lack a capsule or be less encapsulated than a typical schwannoma More challenging to identify from MPNST are the infrequent plexiform schwannomas that develop in deep anatomical sites such as soft tissue 9 or major peripheral nerves 10 These tumors may exhibit enhanced cellularity and mitotic activity Although the likelihood of these tumors developing into cancer is extremely low local recurrence is possible in around half of cases On MRI it usually shows hyper or iso intensity on T1 weighted images and heterogenous hyperintensities on T2 weighted images Pleural schwannoma typically shows fatty degeneration hemorrhage perivascular hyalinization and cystic formation thus giving heterogenous hyperintensities on T2 weighted images Complete surgical removal of pleural schwannoma is the usual treatment 11 Cellular schwannoma is a relatively rare variation Cellular schwannoma is nearly exclusively made up of a fascicular proliferation of well differentiated Schwann cells that are cytologically bland missing Verocay bodies and just slightly exhibiting Antoni B pattern growth 10 of the tumor area 12 13 14 Local recurrence is Variable 5 40 and perhaps greater than in normal schwannomas 15 16 Melanotic schwannoma is an uncommon unique and possibly cancerous neoplasm defined by epithelioid cells with variable sized nuclei substantial melanin deposition in neoplastic cells and associated melanophages 17 Gallery edit nbsp nbsp nbsp Subcutaneous schwannoma nbsp Antoni A area of schwannoma with Verocay bodies one annotated by circle nbsp nbsp nbsp See also editIntranodal palisaded myofibroblastoma List of inclusion bodies that aid in diagnosis of cutaneous conditions Neurofibroma Palisaded encapsulated neuromaReferences edit James WD Berger T Elston D 2006 Andrews diseases of the skin clinical dermatology 10th ed Philadelphia Saunders Elsevier ISBN 978 0 7216 2921 6 a b c Rapini RP Bolognia JL Jorizzo JL 2007 Dermatology 2 Volume Set St Louis Mosby ISBN 978 1 4160 2999 1 Biswas D Marnane CN Mal R Baldwin D September 2007 Extracranial head and neck schwannomas a 10 year review Auris Nasus Larynx 34 3 353 359 doi 10 1016 j anl 2007 01 006 PMID 17376620 a b Hanemann CO Evans DG December 2006 News on the genetics epidemiology medical care and translational research of Schwannomas Journal of Neurology 253 12 1533 1541 doi 10 1007 s00415 006 0347 0 PMID 17219030 S2CID 11854280 Nguyen AH Smith ML Maranda EL Punnen S June 2016 Clinical Features and Treatment of Penile Schwannoma A Systematic Review Clinical Genitourinary Cancer 14 3 198 202 doi 10 1016 j clgc 2015 12 018 PMID 26797586 Fletcher CD Davies SE Benign plexiform multinodular schwannoma a rare tumour unassociated with neurofibromatosis Histopathology 1986 10 971 980 PubMed 3096870 Woodruff JM Marshall ML Godwin TA Funkhouser JW Thompson NJ Erlandson RA Plexiform multinodular schwannoma A tumor simulating the plexiform neurofibroma Am J Surg Pathol 1983 7 691 697 PubMed 6638259 Berg JC Scheithauer BW Spinner RJ Allen CM Koutlas IG Plexiform schwannoma a clinicopathologic overview with emphasis on the head and neck region Hum Pathol 2008 39 633 640 PubMed 18439936 Agaram N P Prakash S Antonescu C R Deep seated plexiform schwannoma a pathologic study of 16 cases and comparative analysis with the superficial variety American Journal of Clinical Pathology 29 1042 1048 2005 PubMed 16006798 Hebert Blouin MN Amrami KK Scheithauer BW Spinner RJ Multinodular plexiform multifascicular schwannomas of major peripheral nerves an underrecognized part of the spectrum of schwannomas J Neurosurg 2010 112 372 382 PubMed 19499977 Iwasaki T 2016 Giant ancient schwannoma of the pleura Commentary Lung India 33 4 449 50 doi 10 4103 0970 2113 184928 PMC 4948239 PMID 27578944 Casadei GP Scheithauer BW Hirose T Manfrini M Van Houton C Wood MB Cellular schwannoma A clinicopathologic DNA flow cytometric and proliferation marker study of 70 patients Cancer 1995 75 1109 1119 PubMed 7850709 Fletcher CD Davies SE McKee PH Cellular schwannoma a distinct pseudosarcomatous entity Histopathology 1987 11 21 35 PubMed 3557324 Wick M R Swanson P E Scheithauer B W Manivel J C Malignant peripheral nerve sheath tumor An immunohistochemical study of 62 cases American Journal of Clinical Pathology 87 425 433 1987 PubMed 2435144 White W Shiu MH Rosenblum MK Erlandson RA Woodruff JM Cellular schwannoma A clinicopathologic study of 57 patients and 58 tumors Cancer 1990 66 1266 1275 PubMed 2400975 Casadei GP Scheithauer BW Hirose T Manfrini M Van Houton C Wood MB Cellular schwannoma A clinicopathologic DNA flow cytometric and proliferation marker study of 70 patients Cancer 1995 75 1109 1119 PubMed 7850709 Mennemeyer R P Hallman K O Hammar S P Raisis J E Tytus J S Bockus D Melanotic schwannoma Clinical and ultrastructural studies of three cases with evidence of intracellular melanin synthesis American Journal of Clinical Pathology 3 3 10 1979 PubMed 534381 External links edit Retrieved from https en wikipedia org w index php title Schwannoma amp oldid 1188128605, wikipedia, wiki, book, books, library,
