The Open Orthopaedics Journal




ISSN: 1874-3250 ― Volume 14, 2020
CASE REPORT

Median Nerve Schwannoma of the Hand and Wrist: 3 Cases



Konstantinos C Xarchas1, *, Georgios Kyriakopoulos1, Maria Vlachou1, Spyros Manthas1
1 Department of Orthopaedics, Athens General Hospital G. Gennimatas, Athens, Greece

Abstract

Tumors of the median nerve are difficult to diagnose and median nerve schwannomas are rare. During a ten-year period, we treated eleven median nerve schwannomas found on the hand (nine) and wrist (two). All the tumors were treated by enucleation under loupe magnification and tourniquet application. All had a favorable result at a mean follow up of five years. We present three of our most typical cases, with schwannomas found on the wrist, palm and thumb. We also review the literature offering a wider view on the pathology, diagnosis and treatment of schwannomas in general.

Keywords: Median, Nerve, Tumor, Neurilemmoma, Schwannoma, Case series, Benign.


Article Information


Identifiers and Pagination:

Year: 2019
Volume: 13
First Page: 290
Last Page: 294
Publisher Id: TOORTHJ-13-290
DOI: 10.2174/1874325001913010290

Article History:

Received Date: 21/05/2019
Revision Received Date: 23/10/2019
Acceptance Date: 14/11/2019
Electronic publication date: 31/12/2019
Collection year: 2019

© 2019 Xarchas et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at Department of Orthopaedics, Athens General Hospital G. Gennimatas, 154, PC 11527, Athens, Greece;
Tel: 00302107768507,00302132032507; E-mail: drkcxr@yahoo.com,






1. INTRODUCTION

Peripheral Nerve Sheath Tumors (PNST) are uncommon, comprising less than 5% of the soft tissue tumors of the upper limb [1Strickland JW, Steichen JB. Nerve tumors of the hand and forearm. J Hand Surg Am 1977; 2(4): 285-91.
[http://dx.doi.org/10.1016/S0363-5023(77)80128-7] [PMID: 197148]
]. The most common amongst them are neurilemmomas, also known as Schwannomas, that are derived from Schwan cells and are more common in the hand and wrist [2Sandberg K, Nilsson J, Søe Nielsen N, Dahlin LB. Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study. Scand J Plast Reconstr Surg Hand Surg 2009; 43(1): 43-9.
[http://dx.doi.org/10.1080/02844310802489079] [PMID: 19153882]
] and neurofibromas, comprised of cells of mixed origin, that seem to be more common in the brachial plexus [3Das S, Ganju A, Tiel RL, Kline DG. Tumors of the brachial plexus. Neurosurg Focus 2007; 22(6)E26
[http://dx.doi.org/10.3171/foc.2007.22.6.27] [PMID: 17613218]
]. Schwannomas are usually solitary tumors arising from the Schwann cells that support the peripheral nerve fibers. Schwannomatosis comprises multiple non-cutaneous Schwannomas, but a very rare condition with 38 cases has been reported in the literature so far [4Chick G, Victor J, Poujade T, Hollevoet N. Sporadic schwannomatosis: A systematic review following the 2005 consensus statement. J Neurol Surg A Cent Eur Neurosurg 2018; 79(5): 408-15.
[http://dx.doi.org/10.1055/s-0038-1655548] [PMID: 29902824]
]. Schwannomas are benign in the vast majority of cases and malignant transformation or relapse post-excision is almost non-existent [5Kim DH, Murovic JA, Tiel RL, Moes G, Kline DG. A series of 397 peripheral neural sheath tumors: 30-year experience at Louisiana State University Health Sciences Center. J Neurosurg 2005; 102(2): 246-55.
[http://dx.doi.org/10.3171/jns.2005.102.2.0246] [PMID: 15739552]
, 6Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
]. They are usually asymptomatic in the early stages, and are not noticed, until they either become palpable, or develop nerve compression [7Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
]. Computerized tomography and ultrasound were originally used as the main imaging modalities, yet recently, Magnetic resonance imaging has become the gold standard in imaging [8Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR Am J Roentgenol 2001; 176(1): 75-82.
[http://dx.doi.org/10.2214/ajr.176.1.1760075] [PMID: 11133542]
]. Treatment consists of intralesional excision by sparing the fascicles where possible, with predictable pain relief and low complication rate/recurrence [6Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
].

Tumors of the median nerve are diagnostically challenging and median nerve schwannomas are rare. During a ten-year period, we treated eleven schwannomas of the median nerve found on the hand (nine) and wrist (two).

All the tumors were treated by enucleation under loupe magnification and tourniquet application. All had a favorable result at a mean follow up of five years. We present three of our most typical cases, with schwannomas located at the wrist, palm and thumb (Table 1).

2. MATERIALS AND METHODS: CASES

2.1. First Case

A 35-year-old male patient complained about a painful mass on his right wrist. His past medical history was clear. Three months prior, he had noticed a mass growing on the palmar surface of his wrist. The mass was small, palpable, immovable in the longitudinal but mobile in the perpendicular axis and it was soft. His chief complaint was his inability to keep up with his job as a guitar player. Upon examination, Tinel sign was positive, with otherwise normal sensory and motor function. MRI revealed a mass eccentric to his median nerve. The patient underwent tumor enucleation under general anesthesia and tourniquet. Loop magnification was used and all fascicles were salvaged. The patient had a difficult postoperative recovery and complained about paresthesias postoperatively, which eventually recovered at the 3 months follow up visit. Tinel’s was negative at the 6-month postoperative visit. (Figs. 1 and 2)

2.2. Second Case

A female patient 60 years of age, presented with a painful palpable mass on her right hand. The mass had been growing for a year and was not mobile. The patient’s medical history was otherwise unremarkable. Tinel’s sign was present without sensory or motor loss. Upon MRI, a mass on the common digital nerve was evident and prominent. Under general anesthesia and tourniquet use, with loop magnification, the mass was surgically enucleated. There were no wound healing problems, or novel neurologic impairment. The patient complained about paresthesias which eventually disappeared at 6 months follow- up visit, along with her Tinel sign.(Fig. 3).

2.3. Third Case

An 80 year old female patient , with a painful mass on the left thumb that had been growing for the two years with no other symptoms. No Tinel’s sign was present, and there was no motor or sensory loss or limitation in thumb motion. The patient had a medical history of atrial fibrillation with a pacemaker and anticoagulant therapy. The patient could not undergo MRI due to her pacemaker. Under regional anesthesia and finger tourniquet, the tumor was enucleated. No wound healing problems or hematoma was observed postoperatively, however the patient complained of paresthesias till the 2 year postoperative visit. (Fig. 4).

At the final follow-up visit, there was no evidence of recurrence or novel neurologic symptoms. Histology was consistent with Neurilemoma in all three cases, and patients reported good pain relief.

3. DISCUSSION

Schwannomas, despite being the commonest of all PNST’s in the upper limb [2Sandberg K, Nilsson J, Søe Nielsen N, Dahlin LB. Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study. Scand J Plast Reconstr Surg Hand Surg 2009; 43(1): 43-9.
[http://dx.doi.org/10.1080/02844310802489079] [PMID: 19153882]
], are rare and consequently often misdiagnosed, or diagnosed postoperatively on the pathology examination. All major nerves of the upper limb can be affected with tumors of the ulnar, radial and median nerves being most commonly encountered, but Schwannomas have also been described affecting the axillary, musculocutaneous, posterior and anterior interossei and digital nerves [2Sandberg K, Nilsson J, Søe Nielsen N, Dahlin LB. Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study. Scand J Plast Reconstr Surg Hand Surg 2009; 43(1): 43-9.
[http://dx.doi.org/10.1080/02844310802489079] [PMID: 19153882]
, 6Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
, 9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
, 10Adani R, Tarallo L, Mugnai R, Colopi S. Schwannomas of the upper extremity: analysis of 34 cases. Acta Neurochir (Wien) 2014; 156(12): 2325-30.
[http://dx.doi.org/10.1007/s00701-014-2218-2] [PMID: 25223747]
].

Neurilemmomas are usually solitary, benign tumors, however multifocal neurilemmomas [11Tang JB, Ishii S, Usui M, Naito T. Multifocal neurilemomas in different nerves of the same upper extremity. J Hand Surg Am 1990; 15(5): 788-92.
[http://dx.doi.org/10.1016/0363-5023(90)90158-N] [PMID: 2229981]
] and multiple neurilemmomas on the same nerve have been described [12Aslam N, Kerr G. Multiple schwannomas of the median nerve: a case report and literature review. Hand Surg 2003; 8(2): 249-52.
[http://dx.doi.org/10.1142/S0218810403001741] [PMID: 15002106]
]. In the previous decade, Schwannomatosis was classified as a distinct clinical entity, with multiple non-cutaneous schwannomas in the absence of signs of neurofibromatosis type 2. It is, however, very rare, with only 38 cases reported so far according to a systematic review by Chick et al [4Chick G, Victor J, Poujade T, Hollevoet N. Sporadic schwannomatosis: A systematic review following the 2005 consensus statement. J Neurol Surg A Cent Eur Neurosurg 2018; 79(5): 408-15.
[http://dx.doi.org/10.1055/s-0038-1655548] [PMID: 29902824]
]. Despite their soft tissue origins, neurilemmomas have also been reported in intraosseous [13Afshar A, Afaghi F. Intraosseous schwannoma of the second metacarpal: case report. J Hand Surg Am 2010; 35(5): 776-9.
[http://dx.doi.org/10.1016/j.jhsa.2010.02.006] [PMID: 20378273]
], subungual [14Kulkarni J, Moholkar A, Patil A. Subungual schwannoma: an uncommon location. J Hand Surg Am 2013; 38(6): 1258-9.
[http://dx.doi.org/10.1016/j.jhsa.2013.03.057] [PMID: 23707022]
] and intramuscular [9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
] locations. In the largest published series, malignant Schwannomas were rare [5Kim DH, Murovic JA, Tiel RL, Moes G, Kline DG. A series of 397 peripheral neural sheath tumors: 30-year experience at Louisiana State University Health Sciences Center. J Neurosurg 2005; 102(2): 246-55.
[http://dx.doi.org/10.3171/jns.2005.102.2.0246] [PMID: 15739552]
] and no malignant transformation was reported at mid-term follow up in a study of 234 benign solitary Schwannomas [9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
]. Ozdemir et al., in their series of 14 cases of median nerve Schwannomas reported no recurrence with a mean follow-up of 12 years [7Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
].

Schwannomas tend to be asymptomatic in the beginning with nothing more than a palpable mass and an insidious onset of symptoms which are reflected in the long time intervals from the onset of symptoms to presentation seen in the largest series with Knight et al reporting a mean of 35 months [9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
] and Ozdemir et al reporting a mean of 25 months [7Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
]. Acute onset of symptoms has been reported in a case of hemorrhaged Schwannoma [15Erlandson RA, Woodruff JM. Peripheral nerve sheath tumors: an electron microscopic study of 43 cases. Cancer 1982; 49(2): 273-87.
[http://dx.doi.org/10.1002/1097-0142(19820115)49:2<273::AID-CNCR2820490213>3.0.CO;2-R] [PMID: 7053827]
, 16Ritt MJ, Bos KE. A very large neurilemmoma of the anterior interosseous nerve. J Hand Surg [Br] 1991; 16(1): 98-100.
[http://dx.doi.org/10.1016/0266-7681(91)90141-A] [PMID: 2007828]
] but it is very rare. The main complaint is a palpable mass with Tinel’s sign being present in most patients (reported range 80-94%) [6Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
, 7Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
, 9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
]. The mass is usually mobile in an axis perpendicular to that of the affected nerve but not in a longitudinal direction. Spontaneous pain, altered sensation and muscle weakness have also been reported, but are not as common [7Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
], and usually present later in the disease process, as the mass increases in size and causes compressive symptoms [17Aydin MD, Kotan D, Keles M. Acute median nerve palsy due to hemorrhaged schwannoma: case report. J Brachial Plex Peripher Nerve Inj 2007; 2: 19.
[PMID: 17892547]
]. In our series, one patient presented early (3 months) with a chief complaint of a palpable mass on his dominant wrist which was probably noticed due to occupational reasons (guitar player). The other two patients presented more than one year after onset of symptoms.

Gadolinium enhanced MRI is useful in the diagnosis of Schwannomas, with the characteristic “target sign”, that is a biphasic or triphasic pattern, where the periphery has a higher intensity on the T2 sequence and low intensity on the Gadolinium enhanced T1 and vice versa on the central part. It was shown to have a specificity of 100% and a sensitivity of 59% in a histologically verified study by Koga et al [18Siqueira MG, Socolovsky M, Martins RS, et al. Surgical treatment of typical peripheral schwannomas: the risk of new postoperative deficits. Acta Neurochir (Wien) 2013; 155(9): 1745-9.
[http://dx.doi.org/10.1007/s00701-013-1818-6] [PMID: 23873125]
]. Distinction between Schwannomas and Neurofibromas is not always easy and radiological signs suggest that the former is in an eccentric position in relation to the parent nerve and heterogenous appearance. Calcifications can be seen in chronic lesions, the so-called ancient Schwannomas [8Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR Am J Roentgenol 2001; 176(1): 75-82.
[http://dx.doi.org/10.2214/ajr.176.1.1760075] [PMID: 11133542]
].

Histological examination reveals a combination of areas with numerous Schwann cells, the Antoni A areas and areas that are relatively hypocellular, the Antoni B areas. Schwannomas tend to be encapsulated and eccentrically placed, thus allowing intralesional excision with fascicle preservation, whereas neurofibromas are usually non-encapsulated and centrally placed, thus hindering fascicle preservation during tumor excision. S-100 staining is strongly positive in Schwannomas which helps in differentiating it from NF [20Stefansson K, Wollmann R, Jerkovic M. S-100 protein in soft-tissue tumors derived from Schwann cells and melanocytes. Am J Pathol 1982; 106(2): 261-8.
[PMID: 6278936]
].

In all cases, enucleation of the lesion under loop magnification should be attempted in an effort to preserve all fascicles [10Adani R, Tarallo L, Mugnai R, Colopi S. Schwannomas of the upper extremity: analysis of 34 cases. Acta Neurochir (Wien) 2014; 156(12): 2325-30.
[http://dx.doi.org/10.1007/s00701-014-2218-2] [PMID: 25223747]
], as was the case in all three of the patients. Pain relief has been shown to be a reproducible result in the vast majority of patients in the literature with rates exceeding 80%, with Tinel’s sign disappearing postoperatively [2Sandberg K, Nilsson J, Søe Nielsen N, Dahlin LB. Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study. Scand J Plast Reconstr Surg Hand Surg 2009; 43(1): 43-9.
[http://dx.doi.org/10.1080/02844310802489079] [PMID: 19153882]
, 3Das S, Ganju A, Tiel RL, Kline DG. Tumors of the brachial plexus. Neurosurg Focus 2007; 22(6)E26
[http://dx.doi.org/10.3171/foc.2007.22.6.27] [PMID: 17613218]
, 6Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
]. Complications consist mainly of novel neurologic impairment and paresthesias have been reported with widely varying rates from 1.5-80% [9Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
, 19Koga H, Matsumoto S, Manabe J, Tanizawa T, Kawaguchi N. Definition of the target sign and its use for the diagnosis of schwannomas. Clin Orthop Relat Res 2007; 464(464): 224-9.
[PMID: 17767081]
]. The most common complication reported are paresthesias that seem to resolve over time [10Adani R, Tarallo L, Mugnai R, Colopi S. Schwannomas of the upper extremity: analysis of 34 cases. Acta Neurochir (Wien) 2014; 156(12): 2325-30.
[http://dx.doi.org/10.1007/s00701-014-2218-2] [PMID: 25223747]
]. Predictive factors for complications are age under 50 years and lesion size over 3 cm [18Siqueira MG, Socolovsky M, Martins RS, et al. Surgical treatment of typical peripheral schwannomas: the risk of new postoperative deficits. Acta Neurochir (Wien) 2013; 155(9): 1745-9.
[http://dx.doi.org/10.1007/s00701-013-1818-6] [PMID: 23873125]
]. In our series, paresthesias were present in all our patients, but were resolved in the first postoperative year Table 1.

Fig. (1)
Intraoperative photo of case 1, median nerve Schwannoma at the wrist.


Fig. (2)
Intraoperative photo of median nerve Schwannoma at the wrist. Prior to mass resection.


Fig. (3)
Intraoperative photo of common digital nerve Schwannoma.


Fig. (4)
Intraoperative photo of Schwannoma of the digital nerve of the thumb.


Table 1
Summary of operated patients' details.


CONCLUSION

Neurilemomas of the median nerve are rare, and can have an insidious onset of symptoms. A high index of suspicion and adequate imaging is necessary to ensure an adequate diagnosis. Enucleation of the tumor with fascicle preservation can yield predictably good outcomes with minimal recurrence rates.

ETHICS APPROVAL AND CONTENT TO PARTICIPATE

Not applicable.

HUMAN AND ANIMAL RIGHTS

Not applicable.

CONSENT FOR PUBLICATION

Not applicable.

STANDARD FOR REPORTING

CARE guidelines have been followed.

FUNDING

None.

CONFLICT OF INTEREST

The author declares no conflict of interest, financial or otherwise.

ACKNOWLEDGEMENTS

Declared none.

REFERENCES

[1] Strickland JW, Steichen JB. Nerve tumors of the hand and forearm. J Hand Surg Am 1977; 2(4): 285-91.
[http://dx.doi.org/10.1016/S0363-5023(77)80128-7] [PMID: 197148]
[2] Sandberg K, Nilsson J, Søe Nielsen N, Dahlin LB. Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study. Scand J Plast Reconstr Surg Hand Surg 2009; 43(1): 43-9.
[http://dx.doi.org/10.1080/02844310802489079] [PMID: 19153882]
[3] Das S, Ganju A, Tiel RL, Kline DG. Tumors of the brachial plexus. Neurosurg Focus 2007; 22(6)E26
[http://dx.doi.org/10.3171/foc.2007.22.6.27] [PMID: 17613218]
[4] Chick G, Victor J, Poujade T, Hollevoet N. Sporadic schwannomatosis: A systematic review following the 2005 consensus statement. J Neurol Surg A Cent Eur Neurosurg 2018; 79(5): 408-15.
[http://dx.doi.org/10.1055/s-0038-1655548] [PMID: 29902824]
[5] Kim DH, Murovic JA, Tiel RL, Moes G, Kline DG. A series of 397 peripheral neural sheath tumors: 30-year experience at Louisiana State University Health Sciences Center. J Neurosurg 2005; 102(2): 246-55.
[http://dx.doi.org/10.3171/jns.2005.102.2.0246] [PMID: 15739552]
[6] Gosk J, Gutkowska O, Urban M, Wnukiewicz W, Reichert P, Ziółkowski P. Results of surgical treatment of schwannomas arising from extremities. BioMed Res Int 2015; 2015547926
[http://dx.doi.org/10.1155/2015/547926] [PMID: 25793198]
[7] Ozdemir O, Ozsoy MH, Kurt C, Coskunol E, Calli I. Schwannomas of the hand and wrist: long-term results and review of the literature. J Orthop Surg (Hong Kong) 2005; 13(3): 267-72.
[http://dx.doi.org/10.1177/230949900501300309] [PMID: 16365490]
[8] Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. AJR Am J Roentgenol 2001; 176(1): 75-82.
[http://dx.doi.org/10.2214/ajr.176.1.1760075] [PMID: 11133542]
[9] Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg Br 2007; 89(3): 382-7.
[http://dx.doi.org/10.1302/0301-620X.89B3.18123] [PMID: 17356155]
[10] Adani R, Tarallo L, Mugnai R, Colopi S. Schwannomas of the upper extremity: analysis of 34 cases. Acta Neurochir (Wien) 2014; 156(12): 2325-30.
[http://dx.doi.org/10.1007/s00701-014-2218-2] [PMID: 25223747]
[11] Tang JB, Ishii S, Usui M, Naito T. Multifocal neurilemomas in different nerves of the same upper extremity. J Hand Surg Am 1990; 15(5): 788-92.
[http://dx.doi.org/10.1016/0363-5023(90)90158-N] [PMID: 2229981]
[12] Aslam N, Kerr G. Multiple schwannomas of the median nerve: a case report and literature review. Hand Surg 2003; 8(2): 249-52.
[http://dx.doi.org/10.1142/S0218810403001741] [PMID: 15002106]
[13] Afshar A, Afaghi F. Intraosseous schwannoma of the second metacarpal: case report. J Hand Surg Am 2010; 35(5): 776-9.
[http://dx.doi.org/10.1016/j.jhsa.2010.02.006] [PMID: 20378273]
[14] Kulkarni J, Moholkar A, Patil A. Subungual schwannoma: an uncommon location. J Hand Surg Am 2013; 38(6): 1258-9.
[http://dx.doi.org/10.1016/j.jhsa.2013.03.057] [PMID: 23707022]
[15] Erlandson RA, Woodruff JM. Peripheral nerve sheath tumors: an electron microscopic study of 43 cases. Cancer 1982; 49(2): 273-87.
[http://dx.doi.org/10.1002/1097-0142(19820115)49:2<273::AID-CNCR2820490213>3.0.CO;2-R] [PMID: 7053827]
[16] Ritt MJ, Bos KE. A very large neurilemmoma of the anterior interosseous nerve. J Hand Surg [Br] 1991; 16(1): 98-100.
[http://dx.doi.org/10.1016/0266-7681(91)90141-A] [PMID: 2007828]
[17] Aydin MD, Kotan D, Keles M. Acute median nerve palsy due to hemorrhaged schwannoma: case report. J Brachial Plex Peripher Nerve Inj 2007; 2: 19.
[PMID: 17892547]
[18] Siqueira MG, Socolovsky M, Martins RS, et al. Surgical treatment of typical peripheral schwannomas: the risk of new postoperative deficits. Acta Neurochir (Wien) 2013; 155(9): 1745-9.
[http://dx.doi.org/10.1007/s00701-013-1818-6] [PMID: 23873125]
[19] Koga H, Matsumoto S, Manabe J, Tanizawa T, Kawaguchi N. Definition of the target sign and its use for the diagnosis of schwannomas. Clin Orthop Relat Res 2007; 464(464): 224-9.
[PMID: 17767081]
[20] Stefansson K, Wollmann R, Jerkovic M. S-100 protein in soft-tissue tumors derived from Schwann cells and melanocytes. Am J Pathol 1982; 106(2): 261-8.
[PMID: 6278936]
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Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


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