MRI of peripheral nerve lesions of the lower limbs

Contrast-enhanced ultrasonography for evaluation of the blood perfusion of sciatic nerves in healthy dogs

Blood supply to the peripheral nerves is essential for fulfilling their structural and functional requirements. This prospective, experimental, exploratory study aimed to assess the feasibility of contrast-enhanced ultrasonography (CEUS) for evaluating blood perfusion of the sciatic nerve in normal dogs. Contrast-enhanced ultrasonography examinations were performed on the bilateral sciatic nerves after bolus injection of Sonazoid™ (0.015 mL/kg) in 12 healthy Beagles for 150 s. Then, qualitative assessment of the wash-in timing, degree and enhancement patterns, and quantitative measurement of the peak intensity and time to peak intensity were performed from the sciatic nerve. The results were compared to those obtained from the adductor muscle around the nerve and caudal gluteal artery. After contrast agent injection, the sciatic nerve was enhanced at approximately 13-14 s, immediately after wash-in of the caudal gluteal artery. The peak intensity of the sciatic nerve was significantly lower than that of the caudal gluteal artery and higher than that of the adductor muscle. The time to peak intensity was significantly slower than that of the caudal gluteal artery; but was not significantly different from that of the adductor muscle. There were no significant differences in the peak intensity and time to peak intensity between the left and right sciatic nerves. These results demonstrate the feasibility of CEUS to assess blood perfusion of the sciatic nerve in healthy dogs qualitatively and quantitatively. This result from healthy dogs could serve as a reference for further studies that evaluate the sciatic nerve under pathological conditions.

An Anatomic Study of the Lateral Dorsal Cutaneous Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications

BACKGROUND

The lateral dorsal cutaneous nerve (LDCN) and the anastomotic branch of the sural nerve (AB) are cutaneous sensory nerves at risk of iatrogenic injury during lateral foot surgery. This study is the first to use a large cohort of high-resolution magnetic resonance images (MRIs) of the ankle to better describe the course of these nerves in vivo in order to aid surgeons intraoperatively. Our study intends to build on the "high and inside" approach to the proximal 5MT by accounting for variations in course of the LDCN and AB.

METHODS

One hundred twenty-five 3-tesla (T) MRI studies of the ankle were analyzed. Three reviewers measured the distance from the LDCN and AB to landmarks including the most proximal aspect of the fifth metatarsal tuberosity (5MT) and the peroneus brevis tendon (PBT).

RESULTS

Mean vertical distance from the LDCN to the 5MT was 0.8 ± 0.2 cm. Presence of an AB was visualized in 59 of 125 studies (47.2%) and was found 2.2 ± 0.5 cm dorsal to the 5MT. The AB was found to become superior to PBT at a horizontal distance 1.9 ± 0.5 cm proximal to the 5MT. The LDCN was found superior to the PBT at its insertion onto the 5MT in approximately 10% (n = 12) of our studies. During these instances, the LDCN was located an average of 0.3 cm dorsal to the PBT.

CONCLUSION

Our proposed "safe zone" for the approach to the proximal 5MT remains superior to the LDCN and inferior to the AB and avoids crossing directly over either nerve in >95% of analyzed MRI studies. This incision begins 1.5 cm dorsal to the most proximal aspect of the 5MT and extends no more than 1 cm posteriorly. Careful dissection and identification of the LDCN and possible AB is necessary prior to further extension of incision.

LEVEL OF EVIDENCE

Level IV, case series.

An Anatomic Study of the Sural Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications

BACKGROUND

The sural nerve (SN) is a sensory cutaneous nerve that is at risk of iatrogenic injury during surgery at the lateral ankle. Prior anatomic studies of the SN are limited primarily to cadaveric studies with small sample sizes. Our study analyzed a large cohort of magnetic resonance images (MRIs) of the ankle to obtain a more generalizable, in vivo sample of distal SN course.

METHODS

A total of 204 3-tesla MRI studies of the ankle were analyzed. Three reviewers measured the distance from the SN to various landmarks including the distal tip of the lateral malleolus (DTLM) and the lateral border of the Achilles tendon (LBA).

RESULTS

Mean vertical distance from SN to DTLM was 2.2 cm (range, 0.9-3.6 cm). Mean horizontal distance from SN to DTLM and to LBA at the level of DTLM was 1.7 cm (range, 0.8-3.0 cm) and 1.9 cm (range, 1.0-2.9 cm), respectively. Mean horizontal distance from SN to LBA at the level of superior Achilles tendon insertion onto the calcaneus (SAI) was 2.6 cm (range, 1.4-3.7 cm), and mean horizontal distance from SN to LBA at 5 cm above SAI was 0.9 cm (range, 0.4-1.8 cm).

CONCLUSION

The variation in SN course observed in our study allowed us to propose "safe zones" for several surgical approaches including the extensile lateral approach to the calcaneus (ELAC), the sinus tarsi approach (STA), the direct lateral approach to the lateral malleolus (DLA), and the posterolateral approach to the ankle (PLA), which we hope will minimize iatrogenic injury to the SN.

LEVEL OF EVIDENCE

Level IV, case series.

Transfer of the Posterior Tibial Tendon for Chronic Peroneal Nerve Palsy

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The common peroneal nerve (CPN) is one of the most frequently injured nerves of the lower extremity.

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One-third of patients who develop CPN palsy proceed to chronic impairment without signs of recovery.

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Ankle-foot orthoses can provide improvement with respect to gait dysfunction and are useful as a nonsurgical treatment option.

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Severe cases of CPN palsy demonstrating no signs of recovery may require operative intervention with tendon transfer.

Intrinsic peripheral nerve and root tumor and pseudotumoral lesions at a tertiary care pediatric hospital

PURPOSE

Tumors affecting peripheral nerves in children are rare. Accurate diagnosis ensures that management is appropriate and timely. A review of intrinsic nerve tumors was completed to differentiate common peripheral nerve lesions based on clinical characteristics and investigations.

METHODS

A retrospective review was conducted for children (< 18 years old) diagnosed with an intrinsic tumor affecting peripheral nerve(s) or roots at the Children's Hospital of Eastern Ontario (CHEO) from 2009 to 2019.

RESULTS

We report 14 children with perineurioma (N = 6), neurofibroma (N = 4), intraneural ganglion cyst (N = 2), or lipomatosis (N = 2). Mean age of symptom onset was 8.2 years (range 0.3 to 17.3 years). Presenting symptoms included muscle weakness (7/14), painless muscle wasting (2/14), contracture (1/14), pain (1/14), or the identification of a painless mass (3/14). Nerve conduction studies (NCS) or electromyography (EMG) were performed in 11/14 patients. MRI was useful at differentiating between these pediatric nerve tumors. Biopsies were performed in nine patients with additional surgical management pursued in four patients.

CONCLUSION

The rare nature of peripheral nerve tumors in children can pose diagnostic challenges. NCS/EMG are important to assist with localization, and MRI is useful to distinguish more benign tumors. Key MRI, clinical, and NCS features can in some cases guide management, potentially avoiding the need for invasive procedures.

MR Neurography: Current Several Issues for Novice Radiologists

말초신경병증의 진단을 위해 MR neurography의 사용이 점차 증가하고 있다. 고대조도와 고해상도로 말초신경을 직접 영상화한 MR 영상을 MR neurography라고 하고, 지방억제 T2 강조영상과 확산강조영상이 흔히 사용되는 시퀀스이다. 작은 직경, 복잡한 해부학적 구조를 가진 말초신경을 합리적 시간 안에 영상화하기 위해서 최신의 isotropic 3차원 기법, 다양한 고속영상기법, post-processing 영상 기법 등이 사용된다. 이런 발전들로 인해 MR neurography가 유용하게 사용되지만 항상 적절한 MR neurography 영상을 얻을 수 있는 것은 아니다. 적절한 MR neurography 영상을 얻기 위해 영상의학과 의사가 고려해야 할 다음의 몇가지 쟁점들이 있다. 이에는 적절한 표준 프로토콜의 선책, 지방억제 기법의 선택, 해상도와 field of view와 slice thickness 간의 상호 관계의 이해, 적절한 post-processing 영상 기법의 적용, 2차원 영상획득 기법과 3차원 영상획득 기법의 장단점, 근위부 말초신경과 말단부 말초신경의 T2 대조도의 차이, 말초신경에 인접한 정맥이 MR neurography에 미치는 영향, 확산강조영상에서 기하학적 왜곡의 발생과 적절한 b value의 선택 등이다. 이런 쟁점들을 잘 이해하는 것이 경험이 적은 영상의학과 의사가 적절한 MR neurography 영상을 얻고, 말초신경병증을 정확히 평가하는 데 많은 도움이 될 것이다.

Diffusion-weighted MR neurography of median and ulnar nerves in the wrist and palm

OBJECTIVES

To investigate the feasibility of diffusion-weighted magnetic resonance neurography (DW-MRN) in the visualisation of extremity nerves in the wrist and palm.

METHODS

Thirty-two volunteers and 21 patients underwent imaging of the wrist and palm on a 3-T MR scanner. In all subjects, two radiologists evaluated the image quality on DW-MRN using a four-point grading scale. Kappa statistics were obtained for inter-observer performance. In volunteers, the chi-squared test was used to assess the differences in nerve visualisation on DW-MRN and axial fat-suppressed proton density weighted imaging (FS-PDWI).

RESULTS

In volunteers, the mean image quality scores for the median nerve (MN) and ulnar nerve (UN) were 3.71 ± 0.46 and 3.23 ± 0.67 for observer 1, and 3.70 ± 0.46 and 3.22 ± 0.71 for observer 2, respectively. The inter-observer agreement was excellent (k = 0.843) and good (k = 0.788), respectively. DW-MRN provided significantly improved visualisations of the second and the third common palmar digital nerves and three branches of UN compared with FS-PDWI (P < 0.05). In patients, the mean image quality scores for the two observers were 3.24 ± 0.62 and 3.10 ± 0.83, inter-observer performance was excellent (k = 0.842).

CONCLUSIONS

DW-MRN is feasible for improved visualisation of extremity nerves and their lesions in the wrist and palm with adequate image quality, thereby providing a supplementary method to conventional MR imaging.

KEY POINTS

• DW-MRN provides adequate image quality for wrist and palm neurography • DW-MRN performs similarly to FS-PDWI in nerve visualisation at the wrist • DW-MRN provides improved visualisation of small nerves in the palm • DW-MRN serves as a supplementary method to evaluate peripheral neuropathies.

Diagnosis and outcome of childhood perineurioma

INTRODUCTION

Intraneural perineurioma is a rare peripheral nerve tumor of childhood and early adulthood. Patients demonstrate progressive muscle weakness and atrophy largely without sensory complaints.

CASE

We report two children with perineurioma affecting the radial and femoral nerves. Electromyography (EMG), ultrasound, and 3-T MR imaging were important tools for localizing perineurioma and permitting its differentiation from other nerve lesions. The first patient underwent surgical excision of the perineurioma and a traditional nerve graft. At 10 months post-operative follow-up, she demonstrated no meaningful recovery of muscle strength compared to her pre-operative assessment. EMG did confirm axonal continuity indicating that reinnervation had occurred via the nerve graft. The second patient underwent a two-staged surgical procedure that included an end-to-side nerve transfer. At 18 months post-operative follow-up, she demonstrated mild improvement in muscle strength and EMG evidence of ongoing reinnervation.

CONCLUSION

The surgical management of perineurioma remains controversial, and reports of clinical recovery after nerve grafts and nerve transfers vary. Nerve transfers have been reported to provide superior results to traditional nerve grafting in adults with post-traumatic plexus injuries. The modest gain in strength of our patient who underwent a nerve transfer raises the question if this may also apply to patients with perineurioma. Additional studies will be required, which must also take into consideration that features of long-standing neuropathy (i.e., limb length discrepancy) have the potential to reduce the likelihood of reinnervation and clinical recovery.

Intraneural ganglion cysts: a systematic review and reinterpretation of the world's literature

OBJECTIVE The etiology of intraneural ganglion cysts has been controversial. In recent years, substantial evidence has been presented to support the articular (synovial) theory for their pathogenesis. The authors sought to 1) perform a systematic review of the world's literature on intraneural cysts, and 2) reinterpret available published MR images in articles by other authors to identify unrecognized joint connections. METHODS In Part 1, all cases were analyzed for demographic data, duration of symptoms, the presence of a history of trauma, whether electromyography or nerve conduction studies were performed, the type of imaging, surgical treatment, presence of a joint connection, intraneural cyst recurrence, and postoperative imaging. Two univariate analyses were completed: 1) to compare the proportion of intraneural ganglion cyst publications per decade and 2) to assess the number of recurrences from 1914 to 2003 compared with the years 2004-2015. Three multivariate regression models were used to identify risk factors for intraneural cyst recurrence. In Part 2, the authors analyzed all available published MR images and obtained MR images from selected cases in which joint connections were not identified by the original authors, specifically looking for unrecognized joint connections. Two univariate analyses were done: 1) to determine a possible association between the identification of a joint connection and obtaining an MRI and 2) to assess the number of joint connections reported from 1914 to 2003 compared with 2004 to 2015. RESULTS In Part 1, 417 articles (645 patients) were selected for analysis. Joint connections were identified in 313 intraneural cysts (48%). Both intraneural ganglion cyst cases and cyst recurrences were more frequently reported since 2004 (statistically significant difference for both). There was a statistically significant association between cyst recurrence and percutaneous aspiration as well as failure to disconnect the articular branch or address the joint. In Part 2, the authors identified 43 examples of joint connections that initially went unrecognized: 27 based on their retrospective MR image reinterpretation of published cases and 16 of 16 cases from their sampling of original MR images from published cases. Overall, joint connections were more commonly found in patients who received an MRI examination and were more frequently reported during the years 2004 to 2015 (statistically significant difference for both). CONCLUSIONS This comprehensive review of the world's literature and the MR images further supports the articular (synovial) theory and provides baseline data for future investigators.

Noninvasive imaging of peripheral nerves

Recent developments in the field of peripheral nerve imaging extend the capabilities of imaging modalities to assist in the diagnosis and treatment of patients with peripheral nerve maladies. Methods such as magnetic resonance imaging (MRI) and its derivative diffusion tensor imaging (DTI), ultrasound (US) and positron emission tomography (PET) are capable of assessing nerve structure and function following injury and relating the state of the nerve to electrophysiological and histological analysis. Of the imaging methods surveyed here, each offered unique and interesting advantages related to the field. MRI offered the opportunity to visualize immune activity on the injured nerve throughout the course of the regeneration process, and DTI offered numerical characterization of the injury and the ability to develop statistical bases for diagnosing injury. US extends imaging to the treatment phase by enabling more precise analgesic applications following surgery, and PET represents a novel method of assessing nerve injury through analysis of relative metabolism rates in injured and healthy tissue. Exciting new possibilities to enhance and extend the abilities of imaging methods are also discussed, including innovative contrast agents, some of which enable multimodal imaging approaches and present opportunities for treatment application.

Magnetic resonance imaging of blood brain/nerve barrier dysfunction and leukocyte infiltration: closely related or discordant?

Unlike other organs the nervous system is secluded from the rest of the organism by the blood brain barrier (BBB) or blood nerve barrier (BNB) preventing passive influx of fluids from the circulation. Similarly, leukocyte entry to the nervous system is tightly controlled. Breakdown of these barriers and cellular inflammation are hallmarks of inflammatory as well as ischemic neurological diseases and thus represent potential therapeutic targets. The spatiotemporal relationship between BBB/BNB disruption and leukocyte infiltration has been a matter of debate. We here review contrast-enhanced magnetic resonance imaging (MRI) as a non-invasive tool to depict barrier dysfunction and its relation to macrophage infiltration in the central and peripheral nervous system under pathological conditions. Novel experimental contrast agents like Gadofluorine M (Gf) allow more sensitive assessment of BBB dysfunction than conventional Gadolinium (Gd)-DTPA enhanced MRI. In addition, Gf facilitates visualization of functional and transient alterations of the BBB remote from lesions. Cellular contrast agents such as superparamagnetic iron oxide particles (SPIO) and perfluorocarbons enable assessment of leukocyte (mainly macrophage) infiltration by MR technology. Combined use of these MR contrast agents disclosed that leukocytes can enter the nervous system independent from a disturbance of the BBB, and vice versa, a dysfunctional BBB/BNB by itself is not sufficient to attract inflammatory cells from the circulation. We will illustrate these basic imaging findings in animal models of multiple sclerosis, cerebral ischemia, and traumatic nerve injury and review corresponding findings in patients.

Sciatic nerve tumor and tumor-like lesions - uncommon pathologies

Sciatic nerve mass-like enlargement caused by peripheral nerve sheath tumors or neurocutaneous syndromes such as neurofibromatosis or schwannomatosis has been widely reported. Other causes of enlargement, such as from perineuroma, fibromatosis, neurolymphoma, amyloidosis, endometriosis, intraneural ganglion cyst, Charcot-Marie-Tooth disease, and chronic inflammatory demyelinating polyneuropathy are relatively rare. High-resolution magnetic resonance imaging (MRI) is an excellent non-invasive tool for the evaluation of such lesions. In this article, the authors discuss normal anatomy of the sciatic nerve and MRI findings of the above-mentioned lesions.

Magnetic resonance neurography of median neuropathies proximal to the carpal tunnel

This review provides magnetic resonance neurography (MRN) imaging appearances of median neuropathy proximal to the carpal tunnel. Carpal tunnel syndrome (CTS) and its imaging have been extensively described in the literature; however, there is a relative paucity of information on the MR imaging appearances of different pathologies of the median nerve proximal to the carpal tunnel.

Detection of blood-nerve barrier permeability by magnetic resonance imaging

The blood-nerve barrier (BNB) separates the endoneurium from the endovascular space and the epineurial connective tissue. An intact BNB is very important for integrity and functions of the nerve fibers within the endoneurial space. Disruption of the BNB which leads to functional and structural impairment of the peripheral nerve plays an important role in many disorders of the peripheral nerve like Wallerian degeneration, inflammatory nerve disorders, and demyelination. So far, this increased BNB permeability can only be assessed ex vivo. Assessing BNB disruption in vivo would be of great value for studying disorders of the peripheral nervous system. Gadofluorine M (Gf), a new amphiphilic contrast agent for MRI, accumulates in rat nerves with increased permeability of the BNB. After application of Gf, T1-weighted MR images show contrast enhancement of nerves with a disrupted BNB. This new tool of assessing BNB permeability in vivo is described.

Intraneural perineurioma of the median nerve: case report and literature review

Intraneural perineurioma is a benign peripheral nerve sheath tumor of perineurial cell origin. We present the case of an intraneural perineurioma of the median nerve in a 23-year-old woman which posed a diagnostic challenge. Ultrasonography was found to be a quick, easy, and effective screening tool for identifying the source of the deficit followed by MRI to further elucidate the lesion. We discuss surgical management options for optimizing functional outcomes when addressing such lesions.

Upper limb nerve injuries in developmental age

Our series includes 105 children with peripheral nerve injuries of the upper limb due to trauma. The aim of this study is to validate our therapeutic approach to peripheral nerve injuries of the upper limb in children and to identify the suitable waiting time before surgical exploration. Case series examination included evaluation of (1) type of lesion; (2) topographical site of nerve injury; (3) motor and sensory outcome; (4) recovery time; (5) results after surgery. Open injuries (Sunderland V) received immediate treatment with direct suturing or nerve grafts or biological tubules in case of loss of nerve substance. After closed nerve injury, a waiting period of variable duration should precede surgery. Most of the cases had peripheral nerve injuries associated to fracture and cutting lesions followed by injuries due to other causes. Open or closed injuries of the median and radial nerves had a generally favorable prognosis, whereas ulnar nerve injuries (both isolated and associated) had a poor prognosis. Stable skeletal fixation is essential in fractures at risk of nerve involvement. During nerve exploration, secondary surgery interventions were never associated. In the absence of adequate clinical and instrumental response, the authors suggest to resort to nerve surgery at 6 months from injury to accelerate recovery time. Secondary surgery should be delayed as patient's recovery time can be very long. (c) 2009 Wiley-Liss, Inc. Microsurgery, 2009.

Intraneural perineurioma of the sciatic nerve in early childhood

Intraneural perineurioma is an uncommon benign neoplasm characterized by focal perineural cell proliferation. The typical course is indolent, with gradual onset and slow progression of motor loss. In early childhood, uncertainty concerning the time of onset can lead to difficulty in distinguishing this potential treatable lesion from congenital and other causes of nerve palsy. In the present case, clinical presentation, electrophysiologic findings, and magnetic resonance imaging findings in a child were compatible with intraneural perineurioma of the lumbosacral trunk and sciatic nerve. Initially, peroneal neuropathy was suspected. The case illustrates that sciatic intraneural perineuriomas do occur in early childhood, and that traction on the sciatic nerve may result in earlier damage to the peroneal nerve than to the tibial nerve, thus mimicking a more peripheral lesion.

Patient outcome after common peroneal nerve decompression

Object

This study examines common peroneal nerve decompression and its effect on nerve function.

Methods

Fifty-one peroneal nerve decompressions were retrospectively reviewed. All patients were evaluated preoperatively and postoperatively for motor and sensory function of the peroneal nerve as well as for pain.

Results

Postoperatively, 40 (83%) of 48 patients who had preoperative motor weakness had improvement in motor function. Likewise, 23 (49%) of 47 patients who had sensory disturbances and 26 (84%) of 31 patients who had preoperative pain improved after surgical decompression of the peroneal nerve.

Conclusions

Common peroneal nerve decompression is a useful procedure to improve sensation and strength as well as to decrease pain.

The Cystic Transverse Limb of the Articular Branch: a Pathognomonic Sign Forperoneal Intraneural Ganglia Atthe Superior Tibiofibular Joint

OBJECTIVE

The preoperative diagnosis of peroneal intraneural ganglia has been difficult to establish, and superior tibiofibular joint connections may not be identified. Misdiagnosis leads to incomplete treatment in that the articular branch connection may not be addressed, which can result in cyst recurrences.

METHODS

We analyzed 20 surgically confirmed cases of paraarticular cysts arising from the superior tibiofibular joint to assess for joint connections and to determine common magnetic resonance imaging characteristics in intraneural ganglia that would allow distinction from extraneural ganglia. We identified and tested three radiographic signs describing the cysts and analyzed cyst morphology (i.e., size, shape, pattern), muscle compartments affected (i.e., for denervation), and neighboring joints (for associated pathology).

RESULTS

Twelve cases of peroneal intraneural ganglia and eight cases of extraneural ganglia were connected to the superior tibiofibular joint. Retrospective review confirmed that these cysts were frequently misdiagnosed, and joint connections often were not recognized. The magnetic resonance imaging appearance of peroneal intraneural ganglia was stereotypical. These intraneural ganglia were tubular, whereas the extraneural were more mass-like. The tail sign was 100% sensitive for identifying joint connections but could not distinguish between intra- and extraneural cysts. The "transverse limb" sign (cystic material within the portion of the articular branch traversing the anterior surface of the fibula) was present in all cases of peroneal intraneural ganglia and none of the extraneural ganglia. The signet ring sign (the eccentric displacement of fascicles by cyst within the epineurium) was 100% sensitive for peroneal intraneural ganglia and 86% specific (it did not identify two cysts that did not extend more proximally into the common peroneal nerve). There was 100% interobserver concordance between the prospective interpretations by a single, blinded, radiologist and a trained first-year medical student with intraoperative findings. In this series, muscle denervation was more common and more pronounced in the intraneural than extraneural ganglia. Abnormalities in neighboring joints were noted nearly universally.

CONCLUSION

This article demonstrates reproducible magnetic resonance imaging features that will easily allow one to identify the joint connection (the tail sign) in paraarticular cysts and also to distinguish between peroneal intraneural and extraneural ganglia (the transverse limb sign and the signet ring sign) at the superior tibiofibular joint with accuracy and confidence and with subsequent improvement in treatment and patient outcomes.

Neurofibroma derived from the deep peroneal nerve: a case report

Neurofibromas may arise anywhere along a nerve from the dorsal root ganglion to the terminal nerve branches; however, peroneal nerve involvement is not common. Surgical resection of neurofibroma with total preservation of nerve function had been thought to be difficult. Here, we report a case of an intermuscular intraneural neurofibroma derived from the deep peroneal nerve in a patient with neurofibromatosis type 1. The diagnostic criteria, characteristics of imaging studies, and operative approach are described. The function of the deep peroneal nerve was preserved, with satisfactory results.

An unusual variant of intraneural ganglion of the common peroneal nerve

A highly unusual variant of an intraneural ganglion of the common peroneal nerve in a 30-year-old male is presented. There was extrusion of the contents of the cyst into the substance of the nerve, dissecting between the fibres and expanding the nerve in such a way that it mimicked an intraneural tumour clinically, radiologically and histologically. A comprehensive review of the entity is undertaken.

Multifocal acquired demyelinating sensory and motor neuropathy presenting as a peripheral nerve tumor

A man with multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), or Lewis-Sumner syndrome, presented with a progressive left lumbosacral plexus lesion resembling a neurofibroma. After 7 years he developed a left ulnar nerve lesion with conduction block in its upper segment. Treatment with intravenous immunoglobulin improved the symptoms and signs of both lesions. We conclude that inflammatory neuropathy must be considered in the differential diagnosis of peripheral nerve tumors, and that unifocal lesions may precede multifocal involvement in MADSAM by several years. In addition, we discuss the clinical features in 9 patients attending a specialist peripheral nerve clinic and review the literature.

Multiple schwannomas of the median nerve: a case report and literature review

We report a case of multiple schwannomas of the median nerve. Multiple schwannomas can be difficult to diagnose on clinical grounds and can be mistakenly diagnosed as carpal tunnel syndrome or ganglia as in our case. Nerve conduction studies helped locate non-visible tumours. Magnetic resonance imaging (MRI) is useful in the preoperative planning of these tumours. The appearances on scanning however can be sometimes confused for ganglia as in this case. Intraneural dissection of the schwannomas was carried out and the pathology is described.