Tumours of peripheral nerves in the upper extremity

Scand J Plast Reconstr Surg Hand Surg, 2009; 43: 4349

ORIGINAL PAPER

Scand J Plast Surg Recontr Surg Hand Surg Downloaded from informahealthcare.com by Nordsjaellands Hospital on 10/15/12 For personal use only.

Tumours of peripheral nerves in the upper extremity: A 22-year epidemiological study

KRISTINA SANDBERG1, JESSICA NILSSON1, NIELS SØE NIELSEN2 & LARS B. DAHLIN1 1

Department of Hand Surgery, Malmo¨ University Hospital, Malmo¨ , Sweden, 2Department of Orthopaedics, Division of Hand Surgery, Gentofte Hospital, Hellerup, Denmark

Abstract Peripheral nerve tumours are uncommon. Our aims were to calculate the incidence and relative frequencies, to define sites of nerve tumours, and to judge preoperative symptoms and outcomes of intervention. The results of 53 patients, with 68 tumours and histopathological diagnoses of true neoplasms, who had been operated on at the Department of Hand Surgery, Malmo¨ , Sweden, between 1986 and 2007, were analysed. Schwannomas were the most common tumour (n 42). The incidence of schwannomas was 0.62/100 000 inhabitants/year in Malmo¨ during that time period. The median nerve was most affected, closely followed by the ulnar and digital nerves. The preferred sites were the forearm, the thumb, and the digits. The most common preoperative symptom was pain. Loss of sensation was the most common postoperative complication. However, 33/53 patients (62%) were completely free of symptoms after excision. Patients should be provided with meticulous information preoperatively.

Key Words: Peripheral nerve tumour, schwannoma, incidence, neurofibroma, preoperative symptoms, postoperative outcomes

Introduction Tumours in peripheral nerves in the upper extremity are uncommon and are among the less common group of swellings and neoplasms in the upper limb or hand [1,2]; the brachial plexus is less affected [3]. Fewer than 5% of all tumours of the hand involve peripheral nerve tumours [4]. Tumours that are benign usually grow slowly with only a few symptoms, while malignant tumours grow faster and are more painful [5]. Fortunately, most tumours seen in clinic are benign. Tumours of peripheral nerves often arise from, and are similar to, cellular portions of the nerve sheath. Knowledge of anatomy and histology of peripheral nerves makes it possible to distinguish between different types of nerve tumours. However, the nomenclature does not follow strict principles. There are different opinions about naming and classification, and also about what kind of tumour is most common. The two most common solitary

tumours are the schwannoma, also referred to as neurilemmoma or neurinoma, and the neurofibroma [58]. Less common are granular cell tumours, neurothekeoma, lipofibromatous hamartoma, and sclerosing perineurioma [911] and malignant nerve tumours. Although the exact reason why peripheral nerve tumours occur is not clear, there is some evidence that chromosomal abnormalities are the main cause. In hereditary disorders, as in certain types of von Recklinghausen disease (neurofibromatosis), studies have shown a predisposition to benign peripheral nerve tumours and genetic defects in chromosomes 22 and 17. Nerve tumours that are found in association with this disease show similar genetic defects in chromosome 22 [6]. Neurofibromatosis type 1 is caused by mutations in the NF1 gene on chromosome 17 and neurofibromin, the gene’s protein product, functions as a tumour suppressor [12]. The exact mechanism by which the other tumours occur is unknown.

Correspondence: Lars B. Dahlin, Department of Hand Surgery, Malmo¨ University Hospital, SE-205 02 Malmo¨, Sweden. Tel: 46 40 33 67 69. Fax: 46 40 92 88 55. E-mail: [email protected]

(Accepted 1 September 2008) ISSN 0284-4311 print/ISSN 1651-2073 online # 2009 Informa UK Ltd. (Informa Healthcare, Taylor & Francis As) DOI: 10.1080/02844310802489079


44

K. Sandberg et al.

Schwannomas

Other nerve tumours

A schwannoma is a benign nerve tumour that arises from Schwann cells [7]. It is usually painless and asymptomatic, but may cause symptoms by compressing surrounding tissues. Palpation may also cause tingling sensations in the area of the affected nerve [13]. They may be located along the peripheral nerve trunk from the brachial plexus down to individual digital nerves. Schwannomas are typically round or oval, not more than 3 cm in diameter, and eccentrically located on the nerve. The lesion is well encapsulated and nerve fascicles are considered not to enter the lesion (however, a small fascicle that enters the schwannomas can often be seen peroperatively). On histopathological evaluation, the Schwann cell is organised into hypercellular (Antoni A), and hypocellular (Antoni B) areas. The hypercellular regions may have palisading nuclei with the cells in an arrangement known as a Verocay body. Haemorrhage, necrosis, and cystic degeneration may also be present. Surgical management involves excision of the tumour. Because nerve fascicles usually do not enter the lesion it can be removed, but with caution, and leave no remaining symptoms. After excision, relapse is unusual. If the lesion does not seem to be encapsulated or to adhere to the surrounding tissue, malignancy should be considered. However, in a true schwannoma this is rare [6].

Other nerve tumours include granular cell tumours, neurothekeoma (in the past referred to as nerve sheath myxoma), lipofibromatous hamartoma, lipoma (originated from nerve), and sclerosing perineurioma [2]. A granular cell tumour is of Schwann-cell origin and usually characterised as a non-tender mass less than 3 cm in diameter. It may or may not involve a nerve. More than 20% of granular cell tumours are found in the upper extremity [6]. The approach is by excisional biopsy. A neurothekeoma originates from either the Schwann or perineural cells. It is slowgrowing, often asymptomatic, and usually less than 1 cm in diameter. The lipofibromatous hamartoma derives from fat and fibrous tissues within the nerve and differs from the previously mentioned tumours by its source of origin. Usually there is infiltration of the median nerve and it is not unusual for patients to show symptoms of carpal tunnel syndrome. A sclerosing perineurioma is composed of perineural cells, and presents typically in young adults as a small nodule most likely to be in the finger or palm. Our aim was to approach the topic of peripheral nerve tumours in the upper extremity by describing the most common types of tumours and compare preoperative symptoms and postoperative outcomes. We also calculated the incidence of, particularly, schwannomas among the population in Malmo¨, a middle sized city in Sweden, and portrayed the relative frequency of the various tumours treated in the hand surgery unit in the same city during a 22year-time period.

Neurofibroma Neurofibromas, like schwannomas, are composed of Schwann cells, perineural cells, and fibroblasts, although the exact cells of origin are controversial. This type of tumour can be seen in patients with von Recklinghausen disease, although one does not have to have the disease to have the tumour. Unlike schwannomas, neurofibromas undergo diffuse proliferation of peripheral nerve components and are seldom encapsulated. The tumour is typically centrally placed, but there are cases of eccentricity [4]. They may also be not clear, and may blend with surrounding tissues. After histological evaluation nerve fibres are seen to spread throughout the tumour mass. This involvement may create a problem on excision, but can be an aid to the surgeon in differentiating between a schwannoma and a neurofibroma. If the tumour mass becomes painful, suddenly changes in size, or is associated with a neurological problem, malignancy should be considered. This is also the case peroperatively if the tumour mass is larger than 2 cm, irregular, or invades into the adjacent tissue [6].

Patients and methods All patients who had had operations at the Department of Hand Surgery at Malmo¨ University Hospital 19862007 for tumours of the peripheral nerves in the upper limb and hand were included (tumours more proximally located, such as the superior trunk of the brachial plexus, were excluded). The criterion for selection was a histopathological record. Two different searches were made because of changes in the diagnostic codes in the year 1997 [ICD 9 (215C), and ICD 10 (D36.1)]. The series were worked through manually and patients suitable for the study were selected. The medical records of the patients were studied to exclude misdiagnoses and untrue neoplasms. Nerve tumours of traumatic origin (such as neuromas) were excluded. The patient’s age, sex, home town, date of operation, type of nerve affected by tumour, preoperative and postoperative symptoms, any result of magnetic resonance imaging, fine needle biopsy, and particularly histopathological records, were noted.

Nerve tumours in upper extremity

tions are excluded from the total number of patients but included in the total number of tumours found.

Based on records of the statistics of the population in the city of Malmo¨ (www.scb.se) during the time interval used in this study the incidence (number of operated cases/100 000 residents/year) of schwannomas was calculated. Only inhabitants of Malmo¨ are included in the calculations, as one cannot anticipate that all schwannomas from the southern part of Sweden were referred to our department.


45

Types of tumours found The most common type of nerve tumour was the schwannoma (Table I, Figure 1). Of the total 53 patients (with 68 tumours) 34 had schwannomas diagnosed (median age 48, range 2389), 13 neurofibromas (median age 41, range 1661), and six other types of nerve tumours [lipofibromatous hamartomas (n 3), granular cell tumour (n 1), sclerosing perineurioma (n 1), and neurothekeoma (n 1)]. Of those patients with schwannoma 19 were male (median age 48, range 2373) and 15 were female (median age 45, range 2689). Of the patients diagnosed with neurofibromas five were male (median age 41, range 3853) and eight were female (median age 43, range 1661).

Results Selection of patients After selection, 53 patients (median age 46, range 16 89) were found to be adequate for this study; 27 were men (median age 46, range 1673) and 26 women (median age 45, range 1689) (Table I). Five of these patients had had more than one operation for more than one tumour; three (1 male/2 female) two, one (male) three, and one (female) four. Those opera-

Table I. Surgically-treated nerve tumours in the upper extremity treated at the Department of Hand Surgery, Malmo¨ University Hospital 19862007. Preoperative symptoms** Type of nerve Age* tumour median (number of value patients/tumours) (range)

Sex*

Pain Paraesthesiae

Postoperative outcome**

Sensory Motor Sensory Motor loss loss Pain Paraesthesiae loss loss

Schwannoma (34/42)

48 19 male (2389) 15 female

25

21

6

5

7

7

8

4

Neurofibroma (13/19)

41 5 male (1661) 8 female

8

3

2

1

3

2

Lipofibromatous hamartoma (3/4) Granular cell tumour (1/1) Sclerosing perineurioma (1/1) Neurothekeoma (1/1)

18 2 male (1659) 1 female

2

1

1

1

1

Nerve affected Axillary 1 Ulnar 13 Median 9 Radial 9 Lateral antebrachial cutaneous 1 Digital 8 Anterior interosseous 1 Ulnar 2 Median 6 Radial 2 Digital 7 Unknown 2 Median 3 Digital 1

16

1 male

1

1

1

1

1

1

Ulnar 1

30

1 female

1

1

Digital 1

49

1 female

1

1

1

Ulnar 1

*Values are calculated from the total number of patients. Patients who suffered from more than one tumour are only counted once. ** Show resulting symptoms of the total number of tumours. If more than one tumour was dissected at the same occasion they are only counted as one.

46

K. Sandberg et al.


Postoperative outcome

Figure 1. Schwannoma located in the ulnar nerve (thick arrow) at excision. Note the small remaining fascicle (thin arrow) going into the schwannoma.

Site The sites of the most common tumours, schwannomas and neurofibromas, are shown in Figure 2. These included shoulder, upper arm, elbow, forearm, wrist, hand, thumb, and digits. The sites of the other tumours were: granular cell tumour (elbow), sclerosing perineurioma (thumb), neurothekeoma (hand), and lipofibromatous hamartoma [forearm (n 2), hand, and digits]. Altogether there were 18 tumours in the forearm, 16 in the thumb and digits, 10 in the upper arm, eight in the hand, nine in the wrist, six in the elbow, and one in the shoulder. Five patients had tumours at two sites and one patient had tumours at three sites. The affected nerves originated mainly from the main trunks in the upper extremity, most commonly from the median nerve (n 18). Seventeen tumours involved the ulnar nerve, 17 the digital nerve, and 11 the radial nerve. Three cases were found in the anterior interosseous nerve, the axillary nerve, and the lateral antebrachial cutaneous nerve, respectively. Two patients showed a diffuse pattern and the main site could not be established. Thirty-one tumours were located on the left and 28 on the right. In nine cases there was no information in the medical records about the exact position of the tumour.

Excision of seven tumours caused postoperative pain or tenderness, of nine numbness and paraesthesiae, of 15 loss of sensation, and of seven motor weakness. In the cases of neurofibroma, sclerosing perineurioma, and neurothekeoma, all patients were free of pain and paraesthesiae postoperatively. For schwannomas slightly more than 80% were free of those symptoms postoperatively (20/25 for pain and 17/21 for paraesthesiae). In 17 cases additional symptoms developed postoperatively, the most common of which was loss of sensation, noted in six cases of schwannomas and one case of each of: neurofibroma, lipofibromatous hamartoma, granular cell tumour, sclerosing perineurioma, and neurothekeoma, respectively. Thirty-three of the 53 patients (62%) were completely free of postoperative symptoms. Recurrence Four patients had a definite recurrent lump and asked to have it removed. Two were neurofibromas, one was a schwannoma, and one was a granular cell tumour. In addition to these, five had multiple

Preoperative symptoms Preoperatively, 38/68 tumours (56%) were clearly symptomatic with direct pain or pain during compression and palpation as the main characteristics (Table I). Twenty-seven tumours resulted in paraesthesiae and numbness, nine in loss of sensation, and seven in motor weakness (patients that had more than one tumour removed at one occasion are counted only once). The duration of symptoms ranged from a few weeks or even days to 15 years (median 1.5 years). In nine cases the duration of symptoms was unknown.

Figure 2. Distribution of surgically-treated schwannomas and neurofibromas in the upper extremity among 53 patients with histopathologically-verified nerve tumours.

Nerve tumours in upper extremity tumours but they were not at exactly the same site as the previous tumour that had been excised, and was therefore not counted in the total number of recurrences.


Incidence of surgically-treated schwannomas The calculated incidence of surgically-treated schwannomas during the period 19862007 is shown in Figure 3, and includes only inhabitants from the city of Malmo¨. In 1986 the population was 229 998 inhabitants, whereas in 2007 it had reached 278 523. The calculated incidence ranged from 0 to 1.70/100 000 inhabitants/year. In eight of the studied years no tumours were found, so the incidence was set to zero. The mean incidence was 0.62/ 100 000 inhabitants/year. Discussion The most common nerve tumour in the upper extremity is a schwannoma, closely followed by a neurofibroma. Artico et al. [14] reported 99 tumours in the upper extremity that were operated on, 64 of which were schwannomas and 35 neurofibromas. However, in a similar study done by Kim et al. [12] of 110 tumours in the upper extremity, 78 were neurofibromas and 32 were schwannomas. These studies have different relative frequencies indicating that there are difficulties in defining which tumour should be at the top of the list. The results may depend on the referral area from which the population is selected. Our patients who were diagnosed with a nerve tumour were middle-aged. Kim et al. [12] showed similar results for schwannomas, but reported a mean age of only 28 for neurofibromas, indicating that patients with neurofibromatosis seek medical treatment earlier in life.

47

The incidence of schwannomas is based only on the fact that many neurofibromas are rarely treated surgically. There are other indications for excision or biopsy in the absence of factors that indicate a malignant tumour [15]. The total incidence of neurofibromas in our study would therefore be based on misleading figures and consequently incorrect. A mean incidence of schwannomas was 0.62/100 000 inhabitants/year. To date, the lack of existing publications about the incidence of schwannomas in the upper extremity means that no exact comparisons can be made. However, with no specific categorisation, Hems et al. [16] found the incidence of all nerve tumours to be about 1/100 000 population/ year. That study, also including tumours of the leg and ankle, consisted only of 14 cases with tumours of the upper extremity. The diagnosis of a peripheral nerve tumour arising within a nerve trunk of the upper extremity may be simple. Usually, there is a swelling, which is painful to palpation and mobile from side to side but not vertically. Side-to-side mobility of the mass from the nerve is more common in cases of benign lesions while malignancy is associated with firmness and immobility [17]. Paraesthesiae in the area of the nerve can be induced by percussion (Tinel’s sign). Knight et al. [18] suggested that these findings are the most useful signs in the diagnosis of a schwannoma. However, the possibility of misdiagnosis is high because the symptoms and signs may not be distinctive. Unfortunately, schwannomas are easily misdiagnosed as ganglia, neurofibromas, or xanthomatous giant cell tumours [13]. In particular, solitary neurofibromas and schwannomas may show identical symptoms. Many diagnostic methods have aided the making of a correct diagnosis, including fine needle biopsy, ultrasonography, and magnetic resonance (MR) imaging. Although MR imaging is costly, it is

2

Incidence of schwannomas (number of 1 excised tumours/ 100.000/year)

0 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 Year Figure 3. Incidence of surgically-treated, and histopathologically-verified, schwannomas at the Department of Hand Surgery, Malmo¨, Sweden 19862007. The incidence over the time period was 0.62/100 000 inhabitants/year.


48

K. Sandberg et al.

still the best way of diagnosing soft tissue tumours and is useful for finding out both the origin of the tumour and its relation to surrounding structures [13,17,19]. Even though MR imaging is often recommended as the best choice of diagnostic method, it is not flawless. MR imaging is currently unable to differentiate between schwannomas and neurofibromas ([13], Nilsson et al., personal communication). The most common preoperative sign was pain (38/53). Kang et al. [13] reported tingling sensations as the predominant preoperative symptom in their patients. The neurological symptoms do not seem to be related to the size of the tumour, but rather to the size of the nerve canal and the relevant degree of compression [13]. In small series of nerve tumours, a topographical scatter is fairly typical [20]. The sites of the tumours and affected nerves do not follow a distinctive pattern, while brachial plexus and more proximal areas (not included in the present study) are probably less affected. The most common sites of schwannomas and neurofibromas were the forearm, thumb, and digits. Holdsworth [21] report of a series of tumours in which 14 of 18 tumours were in the hand and wrist. In another study, two tumours were in the brachial plexus, five in the median nerve [axilla, forearm (n 3), and wrist], two in the ulnar nerve (upper arm and Guyon’s canal) and one in the radial nerve (elbow) [20]. However, in the series of Kang et al. [13] of 20 schwannomas, five were in the upper arm, four in the wrist, four in the hand, three in the forearm, two in the axillary area, and two in the elbow. The decision to operate is based largely on expected improvement in pain and the presence of space-occupying symptoms and the outcome are usually favourable. Surgical treatment of schwannomas and neurofibromas differ in complexity. Even though treatment of schwannomas is difficult, because the natural history of untreated tumours is largely unknown, and most patients present with no motor loss, the approach to neurofibromas is far more complex. The tendency of these tumours is to grow intraneurally and with the infiltration of the nerves it is often necessary to remove the nerve completely. This produces functional disability [14], and an autologous nerve grafting procedure could be necessary. Even if a nerve tumour is carefully dissected from the involved nerve under magnification, transient incomplete nerve palsies sometimes occur [13]. There are two main causes of new postoperative neurological deficits: either the fascicles along the tumour are damaged during dissection, or additional functional nerve structures (not just the tumour-bearing fascicle) are dissected [21]. Sawada et al. [22] discussed three possible reasons

for nerve dysfunction even though the tumour has been completely enucleated. First, schwannomas arise from the nerve sheath and the containing fascicle is always involved. Secondly, longitudinal incisions may divide small numbers of fascicles located over the tumour. Thirdly, intact fascicles not involved in the tumour may be compressed during the operation. Physicians caring for patients with nerve tumours have to weigh carefully the potential risks and benefits of resecting benign peripheral nerve tumours. The decision about how much of a presumably benign tumour to remove rests on surgical judgement. In many cases, it is proper for the patient to participate in the decision-making process [15]. It is therefore important to inform patients of the potential risks of operation. Acknowledgements ¨ sterberg for We thank Anita Larsson and Anna O help with medical records and Tina Folker for secretarial assistance. The present work was based on a student project from The Panum Institute, University of Copenhagen, Denmark. The project was supported by grants from the Swedish Research Council (Medicine), Crafoords Fund for Medical Research, Konsul Thure Carlsson Fund for Medical Research, Region Ska˚ne, and Funds from the University Hospital Malmo¨, Sweden.

References [1] Birch R, Bonney G, Wynn Parry CB. Surgical disorders of the peripheral nerves. Edinburgh: Churchill Livingstone; 1998. [2] Lee DH, Dick HM. Management of peripheral nerve tumors. In: Omer GE, Spinner M, Van Beek AL, editors. Management of peripheral nerve problems. 2nd ed. WB Saunders; 1998. p 597614. [3] Rettenbacher T, Sogner P, Springer P, Fiegl M, Hussl H, zur Nedden D. Schwannoma of the brachial plexus: crosssectional imaging diagnosis using CT, sonography, and MR imaging. Eur Radiol 2003;13:18725. [4] Strickland JW, Steichen JB. Nerve tumors of the hand and forearm. J Hand Surg 1977;2A:28591. [5] Forthman CL, Blazar PE. Nerve tumors of the hand and upper extremity. Hand Clin 2004;20:23342. [6] Idler RS. Benign and malignant nerve tumors. Hand Clin 1995;11:2039. [7] Lundborg G. Handkirurgi-skador, sjukdomar, diagnostik och behandling. 2nd ed. Lund: Studentlitteratur; 1999. [8] Talwalkar SC, Cutler L, Stilwell JH. Multiple plexiform schwannoma of the hand and forearm: a long-term followup. J Hand Surg 2005;30B:35860. [9] Miyake M, Tateishi U, Maeda T, et al. Sclerosing perineurioma: tumour of the hand with a short T2. Skeletal Radiol 2006;35:5436. [10] Huang HY, Sung MT. Sclerosing perineuriomas affecting bilateral hands. Br J Dermatol 2002;146:12933. /

/

/

/

/

/

/

/

/

/

/

/

49

Nerve tumours in upper extremity [11] Canales-Ibarra C, Magarinos G, Olsoff-Pagovich P, OrtizHidalgo C. Cutaneous sclerosing perineurioma of the digits: an uncommon soft-tissue neoplasm. Report of two cases with immunohistochemical analysis. J Cutan Pathol 2003; 30:57781. [12] 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;102:24655. [13] Kang HJ, Shin SJ, Kang ES. Schwannomas of the upper extremity. J Hand Surg 2000;25B:6047. [14] Artico M, Cervoni L, Wierzbicki V, D’Andrea V, Nucci F. Benign neural sheath tumours of major nerves: characteristics in 119 surgical cases. Acta Neurochir (Wien) 1997; 139:110816. [15] Pickard LR, Rose JE. Avoidable complications of resection of major nerve trunk neurofibromas and schwannomas. Neurofibromatosis 1988;1:439. [16] Hems TE, Burge PD, Wilson DJ. The role of magnetic resonance imaging in the management of peripheral nerve tumours. J Hand Surg 1997;22B:5760. /

/

/

/


/

/

/

/

/

/

/

/

[17] Binder DK, Smith JS, Barbaro NM. Primary brachial plexus tumors: imaging, surgical, and pathological findings in 25 patients. Neurosurg Focus 2004;16:E11. [18] Knight DM, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg 2007;89B: 3827. [19] Cerofolini E, Landi A, DeSantis G, Maiorana A, Canossi G, Romagnoli R. MR of benign peripheral nerve sheath tumors. J Comput Assist Tomogr 1991;15:5937. [20] Oberle J, Kahamba J, Richter HP. Peripheral nerve schwannomas an analysis of 16 patients. Acta Neurochir (Wien) 1997;139:94953. [21] Holdsworth BJ. Nerve tumours in the upper limb. A clinical review. J Hand Surg 1985;10B:2368. [22] Sawada T, Sano M, Ogihara H, Omura T, Miura K, Nagano A. The relationship between pre-operative symptoms, operative findings and postoperative complications in schwannomas. J Hand Surg 2006;31B:62934. /

/

/

/

/

/

/

/

/

/

/

/