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

A Recurrent Schwannoma in the Left Distal Ulnar Nerve

While peripheral nerve schwannomas have a relatively low incidence, schwannomatosis, the condition in which one forms multiple recurring schwannomas, is an even rarer phenomenon and can be hard to detect given its ability to mimic other conditions. We report a case of a 35-year-old male who presented with a mass in his left wrist and forearm, volar pain in his forearm, and numbness in his fingers. Magnetic resonance imaging (MRI) revealed a bilobed heterogeneous neural sheath tumor in the distal left ulnar nerve. The tumor was resected including extensive internal neurolysis using a Zeiss operative microscope. Post-operative biopsy confirmed an encapsulated schwannoma. The patient did well initially but developed worsening pain in his forearm and weakness. He had persistent paresthesias in the ulnar nerve distribution. He underwent a repeat MRI almost one year later, which showed thickening of the ulnar nerve proximal to the area of resection with an 8.5 mm hyperintense nodule. The patient underwent a subsequent resection with extensive neurolysis, which confirmed that the mass was a benign non-invasive schwannoma. At six weeks post-surgery, the patient's forearm pain was significantly improved and his range of motion returned to baseline. Our case demonstrates the importance of post-operative follow-up in schwannomas with appropriate imaging if symptoms persist or recur.

Surgery of Schwannoma in the upper limb - sensitivity and specificity of preoperative magnetic resonance imaging and relation between tumour size and symptoms

BACKGROUND

Benign peripheral nerve tumours consist of different types, most commonly Schwannomas. Preoperative Magnetic Resonance Imaging (MRI) is commonly performed before surgery and Pathoanatomical Diagnosis (PAD) confirms the diagnosis. Our aims were to study the utility of MRI and the relation between tumour size and symptoms.

METHODS

Retrospectively, patients, surgically treated for benign nerve tumours between 2008 and 2019, were identified and preoperative MRI, with measurement of tumour size, PAD, symptoms, peroperative details, and symptomatic outcomes of surgery, were analysed.

RESULTS

The sensitivity and specificity to correctly identify Schwannomas with preoperative MRI were 85% and 50%, respectively, based on 30 Schwannomas and nine neurofibromas that were identified. Tumour size did not affect the presence of preoperative symptoms, but patients with sensory dysfunction at last follow-up had larger Schwannomas (p < 0.05). Symptoms as a palpable tumour, paraesthesia and pain improved by surgical excision (p < 0.001, p < 0.001 and p < 0.012, respectively), but sensory and motor dysfunction were common postoperatively. No malignant peripheral nerve sheath tumours (MPNST) were found. Using a surgical microscope, instead of only loop magnification, lowered the risk of perioperative nerve injuries (p < 0.05), but did not further diminish postoperative symptoms.

CONCLUSIONS

Early and accurate diagnosis of Schwannomas is valuable for adequate presurgical preparation and prompt surgical intervention. Preoperative examination with MRI has a high sensitivity, but low specificity; although recent advancement in MRI technology indicates improvement in diagnostic precision. Surgical excision is preferably performed early in conjunction with symptomatic debut to improve outcome.

Ancient Schwannoma of the Radial Nerve: A Case Report

Ancient schwannoma is a very rare subtype of schwannoma. In this report, a case of ancient schwannoma in the upper extremity is reported. A 40-year-old man presented with a slowly growing tumor in the right forearm. He underwent surgery to remove the tumor. Investigation revealed an ancient schwannoma originated from the right radius. Careful preoperative imaging evaluation is important for correct preoperative diagnosis and surgical strategy.

Benign nerve tumours in the upper limb: a registry-based study of symptoms and surgical outcome

Surgery for benign nerve tumours is performed for pathoanatomical diagnosis and symptomatic relief, but might cause residual problems. We aimed to assess patient-reported symptoms and disability before and after surgery at a national level. In total, 206 cases surgically treated for a benign peripheral nerve tumour 2010-2019 registered in the Swedish Quality Registry for Hand Surgery (HAKIR; response rates 22-34%) were analysed. Surgery reduced overall disability in the affected limb (QuickDASH 18/100 [IQR 5-36] preoperatively and 5/100 [IQR 0-22] 12 months postoperatively), improved ability to perform daily activities (HQ-8; 11/100 [IQR 0-50] preoperatively and 0/100 [IQR 0-20] 12 months postoperatively) and decreased three evaluated pain modalities: pain at rest (HQ-8; 20/100 [IQR 0-40] preoperatively and 0/100 [IQR 0-10] 12 months postoperatively), pain on motion without load (HQ-8; 20/100 [IQR 0-40] preoperatively and 0/100 [IQR 0-10] 12 months postoperatively), and pain on load (HQ-8; 24/100 [IQR 1-69] preoperatively and 1/100 [IQR 0-30] 12 months postoperatively). Cold sensitivity was a minor problem both before and after surgery (HQ-8; 0/100 [IQR 0-30] preoperatively and 1/100 [IQR 0-40] 12 months postoperatively). We conclude that surgery for benign peripheral nerve tumours provides good symptomatic relief with low risk for residual problems.

Myofibroma mimicking peripheral nerve sheath tumour with ulnar nerve compression symptoms

We report a case of myofibroma encasing the ulnar nerve on the medial aspect of the left arm with motor and sensory deficit secondary to compression. Initially, the tumour appeared to be a benign peripheral nerve sheath tumour based on preoperative imaging, with clinical examination positive for left hand clawing and a positive Wartenberg's and Froment's sign. However, intraoperative dissection demonstrated that the mass did not originate from the ulnar nerve proper, lowering suspicion for a peripheral nerve sheath tumour. Histopathological analysis showed spindle cell neoplasm, consistent with myofibroma. The patient underwent hand occupational therapy subsequently, with improvement of grip strength from 5 lb to 12 lb by 4 months postoperatively and resolution of clawing of the hand postoperatively. We discuss differentiating features for this rare occurrence of solitary adult myofibroma, where the final diagnosis was only made after formal histopathological analysis.

Natural History of Brachial Plexus, Peripheral Nerve, and Spinal Schwannomas

BACKGROUND

Management of sporadic schwannomas is often dictated by a patient's clinical presentation and the tumor's behavior. For patients who are managed nonsurgically, there are little data available about the expected natural history.

OBJECTIVE

To evaluate the natural history and growth patterns of extracranial schwannomas including tumors of the distal peripheral nerves, spine, and brachial plexus.

METHODS

A retrospective review was performed to identify patients with nonsyndromic extracranial schwannomas at a single tertiary care institution diagnosed between 2002 and 2019. Patient data and tumor characteristics including volume were recorded.

RESULTS

Two hundred twenty-seven patients were identified (mean age 51 years, 42% male, average of 27.8-month follow-up). Tumor location was distal peripheral nerve in 82, brachial plexus in 36, and paraspinal in 109. At the time of diagnosis, peripheral lesions were significantly larger than spinal (59 m 3 vs 13 cm 3 ) and brachial plexus lesions (15 cm 3 ). Distinct growth patterns were seen with both distal peripheral nerve and spinal lesions; 34/82 peripheral nerve lesions had fast growth (β = 0.176%/day), and 48 had slow growth (β = 0.021%/day; P < .01). Spinal schwannomas similarly had 30 fast-growing (β = 0.229%/day), 16 moderate-growing (β = 0.071%/day), and 63 slow-growing (β = 0.022%/day; P = .03) subtypes. The brachial plexus had relatively homogeneous growth patterns (β = 0.065%/day). Females had 2.9 times greater odds of having the fast-growing subtype.

CONCLUSION

Distinct growth patterns were seen in extracranial sporadic schwannomas based on tumor location and patient demographics. Fast (>80% volume change per year) vs slow (5%-10% per year) tumor growth can often be ascertained within 2 follow-up images. Awareness of these patterns might have implications for patient counseling and therapeutic decision-making.

Clinical results after surgical resection of benign solitary schwannomas: A review of 150 cases

INTRODUCTION

Peripheral nerve schwannomas are the most common nerve tumors. While they are efficiently treated with surgery, the risk of neurological complications, especially sensory deficits, remains debated.

HYPOTHESIS

We postulate that rates of post-operative sensory deficits in peripheral schwannoma surgery are low and are not increased in schwannomas of the hand, in which preservation of discriminative tact is of prime functional importance.

MATERIALS AND METHODS

A retrospective multicenter study was carried out on 150 patients with an isolated peripheral schwannoma operated between 2002 and 2018, including 11 patients with schwannomas of the hand. All cases were reviewed preoperatively and postoperatively with a detailed exam of the neurological status.

RESULTS

Most schwannomas were located in the lower limbs (58%). The two main affected trunks were the posterior tibial nerve in the lower limb and the median nerve in the upper limb. The average preoperative tumor volume measured on MRI was 2.93 cm³ [0.11 cm³-25 cm³]. The most common preoperative symptoms were paresthesia (77.1%) and pseudo-Tinel sign (55.7%). Less frequently, pain (50.3%) and hypoesthesia (18.1%) were observed. On the other hand, preoperative neurological motor manifestations remained exceptional (3.3%). The rates of new post-operative motor deficits, paresthesias, and sensory deficits were 4.6%, 10.9% and 8% respectively and were not increased in schwannomas of the collateral nerves of the hand.

CONCLUSION

Surgical resection is a safe procedure for peripheral nerve schwannoma treatment with satisfying functional results and an acceptable risk of nerve injury, especially for sensory function.

LEVEL OF PROOF

D; Multicenter retrospective study.

Schwannoma of the Upper Limb: Retrospective Study of a Rare Tumor with Uncommon Locations

Background: Although schwannoma (neurilemmoma) is the most common tumor of the peripheral nerve, its low incidence, slow growth and vague symptoms often lead to misdiagnosis or delayed diagnosis. The aim of the study is to present a series with a large number of schwannomas in the upper limbs, some with very rare occurrence. Methods: We report 17 patients with a mean age of 58.5 years and upper limb schwannomas, located on the median, ulnar and radial nerves, but also on the posterior interosseous nerve and digital collateral nerves. The diagnosis was made by clinical examination and imaging tests, and in no case was a preoperative biopsy performed. Surgical treatment was established based on symptoms or aesthetic concerns. In all cases, a diagnosis of schwannoma was confirmed through histopathological and immunohistochemical examinations. Results: For all patients, a complete tumor enucleation was performed under a surgical microscope. No recurrence was recorded at 2 years after surgery. Patient satisfaction was good, with complete socio-professional integration in all cases. Conclusions: Although more frequently present on the main nerve trunks, schwannoma may be present on the collateral digital nerves in rare cases. A correct technique with complete tumor excision offers excellent postoperative outcomes and avoids recurrences.

Evidence base for investigative and therapeutic modalities in chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy

Chronic inflammatory demyelinating polyneuropathy, its variants and multifocal motor neuropathy belong to a spectrum of peripheral nerve disorders with complex dysimmune disease mechanisms. Awareness of the unique clinical phenotypes but also heterogeneity between patients is vital to arrive at early suspicion and ordering appropriate tests. This includes requirements for optimal electrodiagnostic protocol, aimed to capture sufficient electrophysiologic evidence for relevant abnormalities, a case-based approach on the eventual need to further expand the diagnostic armamentarium and correct reading of their results. Considerable phenotypical variation, diverse combinations of abnormalities found on diagnostic tests and heterogeneity in disease course and treatment response, all contribute to widespread differences in success rates on timely diagnosis and optimal treatment. We aim to provide a practical overview and guidance on relevant diagnostic and management strategies, including pitfalls and present a summary of the relevant novel developments in this field.

Peripheral nerve tumors of the hand: Clinical features, diagnosis, and treatment

The majority of the tumors arising from the peripheral nerves of the hand are relatively benign. However, a tumor diagnosed as malignant peripheral nerve sheath tumor (MPNST) has destructive consequences. Clinical signs and symptoms are usually caused by direct and indirect effects of the tumor, such as nerve invasion or compression and infiltration of surrounding tissues. Definitive diagnosis is made by tumor biopsy. Complete surgical removal with maximum reservation of residual neurologic function is the most appropriate intervention for most symptomatic benign peripheral nerve tumors (PNTs) of the hand; however, MPNSTs require surgical resection with a sufficiently wide margin or even amputation to improve prognosis. In this article, we review the clinical presentation and radiographic features, summarize the evidence for an accurate diagnosis, and discuss the available treatment options for PNTs of the hand.

Diffusion tensor imaging and tractography for preoperative assessment of benign peripheral nerve sheath tumors

PURPOSE

To evaluate the diagnostic value of fiber tractography and diffusivity analysis generated from 3D diffusion-weighted (DW) sequences for preoperative assessment of benign peripheral nerve sheath tumors.

METHOD

MR imaging at 3 T was performed in 22 patients (mean age 41.9 ± 17.1y, 13 women) with histologically confirmed schwannomas (N = 18) and histologically confirmed neurofibromas (N = 11), including a 3D DW turbo spin echo sequence with fat suppression. Diffusion tensor parameters were computed and fiber tracks were determined. Evaluation was performed by two radiologists and one orthopedic surgeon blinded for final diagnosis. Mean diffusivity was computed to allow further assessment of tumor microstructure. Preoperative fascicle visualization was graded, fascicles were categorized regarding anatomical location and amount of fascicles surrounding the tumor. The agreement of imaging findings with intraoperative findings was assessed.

RESULTS

On 78.3 % of the DTI images, the fascicle visualization was rated as good or very good. Tractography differences were observed in schwannomas and neurofibromas, showing schwannomas to be significantly more often located eccentrically to the nerve (94.8 %) than neurofibromas (0 %, P < 0.01). Fascicles were significantly more often continuous (87.5 %) in schwannomas, while in neurofibromas, none of the tracks was graded to be continuous (0 %, P = 0.014). A substantial agreement between fiber tracking and surgical anatomy was found regarding the fascicle courses surrounding the tumor (κ = 0.78). Mean diffusivity of schwannomas (1.5 ± 0.2 × 10^-3 mm²/s) was significantly lower than in neurofibromas (1.8 ± 0.2 × 10^-3 mm²/s; P < 0.001). The Youden index showed an optimal cutoff at 1.7 × 10^-3 mm²/s (sensitivity, 0.91; specificity, 0.78; J = 0.69).

CONCLUSIONS

Preoperative diffusion tensor imaging allowed to accurately differentiate between schwannomas and neurofibromas and to describe their location in relation to the nerve fascicles for preoperative planning.

Retrospective Analysis of 20 Patients Affected by Schwannomas in the Upper and Lower Limbs

Objective  To analyze the epidemiological profile and evolution of 20 patients diagnosed with upper- and lower-limb schwannomas.

Methods  A group of patients was defined for a retrospective evaluation comprising the period between February 2002 and June 2018, in which we studied and evaluated 20 medical records of patients undergoing surgery due to schwannoma; the diagnosis was confirmed by an anatomopathological examination.

Results  Male and female patients were equally affected. The average age was 50.85 years, ranging from 12 to 77 years. There was a predominance of the upper limb and of the flexor face. The most affected nerve was the ulnar nerve. In total, 6 (30%) patients had transient postoperative complications. No cases of tumor recurrence were identified.

Conclusion  Schwannoma is a rare and difficult-to-diagnose lesion. It should always be considered as a hypothesis when facing a soft-tissue tumor affecting the limbs. The Tinel sign should be regarded, given its higher correlation with complications. The patients should be informed of the possible postoperative complications, which are frequent but usually transient.

Median Nerve Schwannoma of the Hand and Wrist: 3 Cases

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.

Retrospective Analysis of 20 Patients With Schwannomas: Magnetic Resonance Imaging Characteristics, Pain, and Outcomes Following Excision

A Tinel's sign, a percussion-induced, painful sensation, has been reported as the most useful sign for diagnosing a schwannoma. On magnetic resonance imaging, schwannomas often exhibit a split fat sign and a target sign. The typical treatment for schwannomas is surgical excision; however, excision often results in high rates of neurological deficit. The authors retrospectively reviewed 20 patients who underwent excision of a schwannoma from 2007 to 2015. Twenty patients presented with a split fat sign and 12 patients presented with a Tinel's sign on magnetic resonance imaging. Only 3 patients presented with a target sign on magnetic resonance imaging. The operative approach involved removing the schwannoma, preserving the nearby nerve fascicles, and leaving the epineurium open. Follow-up ranged from 3 to 91 months (average, 29 months). At final follow-up, all patients were pain free. Nineteen patients had normal sensation and full function of their affected limb. One patient developed postoperative posterior interosseous nerve palsy. A Tinel's sign, preoperative pain, and a split fat sign on preoperative magnetic resonance imaging are the clinical symptoms most useful for diagnosing a schwannoma. Schwannomas can be safely removed via intracapsular surgical excision with minimal complications, yielding eradication of preoperative pain, normal sensation, and full function. [Orthopedics. 2017; 40(6):e1036-e1043.].

Benign tumors affecting the median nerve. Case series report of diagnostic and surgical strategies

Objective

The aim of this study was to describe the strategies adopted in this institution to diagnose and treat patients with benign tumors affecting the median nerve.

Methods

A retrospective chart review study of all patients operated on between 2010 and 2015. Histology, symptoms, complementary exams, surgical techniques performed, and demographic characteristics were analyzed.

Results

Fifty-four patients were included in the study. There were three neurofibromas, six schwannomas, 15 lipofibromatous hamartomas, three hemangiomas, 12 lipomas, one benign fibrohistiocytoma, and 14 synovial cysts. Complete tumoral resection was performed in 32 cases, partial resection in five, segmented nerve resection in one, nerve decompression in eight, and amputation for macrodactyly in eight.

Conclusions

The most important recommendations on treating benign tumors of the median nerve are related to the clinical symptoms, tumoral growth, and tumoral nature. The surgical approach resulted in good function for 60% of the patients. However, lipofibromatous hamartomas, hemangiomas, and neurofibromas were associated with preoperative functional deficit. It may be inferred that the diagnosis and treatment of these tumors should be performed earlier.

Case report: Intraneural perineurioma of the sciatic nerve in an adolescent - strategies for revealing the diagnosis

Diagnosis of intraneural conditions can be revealed by a combination of clinical examination, electrophysiology, magnetic resonance imaging (MRI), and targeted fascicular biopsy with subsequent microscopic analyses.

Median nerve schwannoma: A case and review of literature

We report a case of a median nerve schwannoma, a rare type of a benign tumor of Schwann cells that presents as a palpable and painful mass on the flexor aspect of the forearm. Schwannomas of the median nerve make up 0.1–0.3% of all hand tumors. Symptoms are caused by an entrapment syndrome resulting from the growing tumor. Pain is the most common complaint of schwannomas. Imaging studies include computed tomography and magnetic resonance imaging and ultrasound. It is difficult to differentiate schwanommas from neurofibromas solely on the basis of a radiological investigation. Tumors of the median nerve are diagnostically challenging and median nerve schwannomas are rare. Diagnostic pearls are described to facilitate a more accurate and timely diagnosis. These characteristics include mobility, Tinel's sign, S-100 histological staining, and Antoni patterns. With a correct diagnosis, the tumor can be extirpated with preservation of nerve function and a low risk of recurrence.

Diffusion tensor tractography for the surgical management of peripheral nerve sheath tumors

OBJECT

Peripheral nerve sheath tumors (PNSTs) are uncommon but bear a significant risk of malignancy. High-resolution MRI is the standard technique for characterizing PNSTs. However, planning the appropriate extent of resection and subsequent reconstructive strategies is highly dependent on the intraoperative findings because preoperative MRI evaluation can be insufficient. Diffusion tensor tractography (DTT) represents a recently developed advanced MRI technique that reveals the microstructure of tissues based on monitoring the random movement of water molecules. DTT has the potential to provide diagnostic insights beyond conventional MRI techniques due to its mapping of specific fibrillar nerve structures. Here, DTT was applied to evaluate PNSTs and to examine the usefulness of this method for the correct delineation of tumor and healthy nerve tissue and the value of this information in the preoperative planning of surgical interventions.

METHODS

In this prospective study, patients with the clinical symptoms of a PNST were investigated using DTT 3-Tesla MRI scans. Image data processing and tractography were performed using the FACT (fiber assessment by continuous tracking) algorithm and multiple-regions-of-interest approach. The surgical findings were then compared with the results of the DTT MRI scans. Preoperative fascicle visualization and the correlation with the intraoperative findings were graded.

RESULTS

In a 21-month period, 12 patients with PNSTs were investigated (7 female and 5 male patients with a mean age of 46.2 ± 19.2 years). All patients underwent surgical removal of the tumor. Schwannoma was the most common benign histopathological finding (n = 7), whereas 2 malignant lesions were detected. In 10 of 12 patients, good preoperative nerve fascicle visualization was achieved using DTT scans. In 9 of 10 patients with good preoperative fascicle visualization, good intraoperative correlation between the DTT scans and surgical anatomy was found.

CONCLUSIONS

DTT properly visualizes the peripheral nerve fascicles and their correct anatomical relation to PNST. DTT represents a promising new method for the preinterventional planning of nerve tumor resection.

Schwannomas of the upper extremity: analysis of 34 cases

BACKGROUND

Schwannomas are the most common benign tumours developing in peripheral nerves. They usually present as a slow-growing mass, sometimes associated with pain and paraesthesia. The aim of this study is to define the correct preoperative diagnosis, to review the surgical treatment employed and to evaluate short- and long-term neurological deficits.

METHODS

Thirty-four patients affected by schwannoma in the upper limbs were treated in the period 1995-2011. In 15 patients the tumour was located on the ulnar nerve, in 8 on the median nerve, in 2 on the radial nerve, in 1 on the anterior interosseous nerve, in 1 on the muscle-cutaneous nerve, and in the remaining 7 on the digital nerves. All patients were surgically treated using a microsurgical approach.

RESULTS

The enucleation of the mass was possible without fascicle lesion in 12 cases. In 22 cases resection of the indissociable fascicles was performed. Postoperative paraesthesia was present in 28 out of 34 treated patients; this clinical sign regressed in a mean period of 12 months in 27 patients.

CONCLUSIONS

When approaching a palpable mass in the upper limbs, the possibility of a peripheral nerve tumour should always be considered. It is important to look for typical signs of schwannomas, such as a positive Tinel sign and peripheral paraesthesia. Imaging assessment with magnetic resonance imaging (MRI) and ultrasonography enables the determination of where the tumour takes its origin and from which nerve. Microsurgical techniques and know-how are recommended in approaching the resection in order to respect as many nerve fibres as possible.

[Giant schwannoma of musculocutaneous nerve (a case report)]

Schwannoma is a tumor that develops from nerve sheath. The authors report an original observation of a giant schwannoma developed in the arm depending on the musculocutaneous nerve. The diagnosis was based on MRI appearance. Confirmation of the diagnosis was made by histological examination. Surgical treatment was resection, taking care preserving adjacent nerve fibers. This allowed recovery without any sequela. Recurrence rate and potential for malignant transformation of this type of tumor is low.

Dendritic fibromyxolipoma adherent to the median nerve in the forearm

We describe a 65-year-old woman with a tumour adherent to the median nerve in the left forearm that was found to be a dendritic fibromyxolipoma, a distinctive benign soft tissue lesion possibly related to a myxoid spindle cell lipoma; it is a solitary fibrous tumour that may be mistaken for a sarcoma. The tumour was successfully excised with no complications.

[Neurogenic tumors of the mediastinum in adults]

In adults, mediastinal neurogenic tumours constitute the third group of mediastinal tumours, after thymomas and lymphomas. If the group of neurogenic tumour is frequent, each type of tumour is relatively unusual in everyday's clinic. Among them, nerve sheath tumours are the more frequent, followed by tumour of the autonomic system. Askin tumour remains uncommon. Treatment of this tumour requires complete preoperative work-up, including standard radiography, CT-scan, MRI, and sometimes nuclear imaging. In most cases, the treatment is based on surgical resection, and may be associated with radiotherapy or chemotherapy in case of malignant tumour or incomplete resection. Better understanding of these tumours, including their molecular abnormalities, may lead to new changes in their classifications, and to their management.

Fibrolipomatous hamartoma in the median nerve in the arm - an unusual location but with MR imaging characteristics: a case report

Fibrolipomatous hamartoma of the median nerve are usually located distally in the forearm and may have characteristic features on MR imaging. Here we report a patient with an extensive fibrolipomatous hamartoma at an unusual location proximally in the arm, where a preoperative MR imaging was pathognomonic and diagnosis was verified by an incisional biopsy. We suggest that MRI should be performed in cases with nerve dysfunction without an obvious cause after a thorough clinical examination.

Magnetic resonance imaging of peripheral nerve tumours in the upper extremity

Clinical assessment and various diagnostic tools, particularly magnetic resonance imaging (MRI), of tumours of peripheral nerves are used to get an accurate diagnosis and to plan surgical intervention. Our purpose was to examine the usefulness of MRI in assessing nerve tumours in the upper extremity. Medical records of 19 patients (20 MRI examinations) with 29 histopathologically verified benign nerve tumours were examined retrospectively. In 12/20 cases MRI suggested a correct diagnosis of the type of nerve tumour. An additional 3/20 cases had an uncertain diagnosis, but nerve relations to the tumour were established. In 5/20 cases MRI gave a doubtful diagnosis with no suspicion of the tumour being located in a nerve trunk. MRI can localise and diagnose a nerve tumour in the upper extremity in 75% of cases, but it is difficult to specify the type of tumour.