MRI features of benign peripheral nerve sheath tumors: how do sporadic and syndromic tumors differ?

OBJECTIVES

To compare MRI features of sporadic and neurofibromatosis syndrome-related localized schwannomas and neurofibromas.

METHODS

In this retrospective study, our pathology database was searched for "neurofibroma" or "schwannoma" from 2014 to 2019. Exclusion criteria were lack of available MRI and intradural or plexiform tumors. Qualitative and quantitative anatomic (location, size, relationship to nerve, signal, muscle denervation) and functional (arterial enhancement, apparent diffusion-weighted coefficient) MRI features of sporadic and syndrome-related tumors were compared. Statistical significance was assumed for p < 0.05.

RESULTS

A total of 80 patients with 64 schwannomas (sporadic: 42 (65.6%) v. syndrome-related: 22 (34.4%)) and 19 neurofibromas (sporadic: 7 (36.8%) v. syndrome-related: 12 (41.7%)) were included. Only signal heterogeneity (T2W p=0.001, post-contrast p=0.03) and a diffused-weighted imaging target sign (p=0.04) were more frequent with schwannomas than neurofibromas. Sporadic schwannomas were similar in size to syndrome-related schwannomas (2.9±1.2cm vs. 3.7±3.2 cm, p = 0.6), but with greater heterogeneity (T2W p = 0.02, post-contrast p = 0.01). Sporadic neurofibromas were larger (4.6±1.5cm vs. 3.4±2.4 cm, p = 0.03) than syndrome-related neurofibromas, also with greater heterogeneity (T2W p=0.03, post-contrast p=0.04). Additional tumors along an affected nerve were only observed with syndrome-related tumors). There was no difference in apparent diffusion coefficient values or presence of early perfusion between sporadic and syndrome-related tumors (p > 0.05).

CONCLUSIONS

Although syndrome-related and sporadic schwannomas and neurofibromas overlap in their anatomic, diffusion and perfusion features, signal heterogeneity and presence of multiple lesions along a nerve are differentiating characteristics of syndrome-related tumors.

When biopsy goes wrong: a case series of misdiagnoses and complications from biopsies of masses of unknown origin potentially originating from a peripheral nerve

OBJECTIVE

Biopsies of peripheral nerve tumors (PNTs) are often used to plan an efficient treatment strategy. However, performing a biopsy is controversial when the mass is likely to be a benign PNT (BPNT). The aim of this study was to evaluate the side effects of biopsies in patients with potential PNTs.

METHODS

A retrospective and cross-sectional study was conducted on 24 patients who underwent biopsy of a mass of unknown origin potentially originating from a peripheral nerve (MUOPON), performed in nonspecialty services, and who were later referred to the authors' service for resection of their lesion between January 2005 and December 2022. The patients were evaluated for pain score, presence of a motor or sensory deficit, biopsy diagnosis, and definitive histopathological postsurgical diagnosis.

RESULTS

The location of the tumor was supraclavicular in 7 (29.2%) patients, in the axillary region in 3 (12.5%), in the upper limb in 7 (29.2%), and in the lower limb in 7 (29.2%). Twenty-one (87.5%) patients were evaluated by MRI before biopsy, and 3 (12.5%) underwent ultrasound. One patient did not have an examination before the procedure. Based on the biopsy findings, 12 (50%) analyses had an inconclusive histopathological result. The preexisting pain worsened, as measured 1 week after biopsy, in all patients and had remained unchanged at the first evaluation by the authors (median 3 months, range 2-4 months). In 1 case, the open biopsy had to be interrupted because the patient experienced excruciating pain. Four (16.7%) patients developed motor deficits. Subsequent surgery was hampered by scar formation and intratumoral hemorrhage in 5 (20.8%) patients. The initial diagnosis obtained by biopsy differed from the final histopathological diagnosis in all patients, of whom 21 (87.5%) had BPNTs, 2 (8.3%) malignant peripheral nerve sheath tumors, and 1 (4.2%) an ancient schwannoma.

CONCLUSIONS

Biopsies of PNTs are controversial and may result in misdiagnosis, neuropathic pain, or neurological deficit due to axonal damage, and they may also hinder microsurgical resection when if performed when not indicated. Indications for biopsy of an MUOPON must be carefully considered, especially if BPNT is a possible diagnosis.

Plexiform neurofibroma (Hamartoma) of the median nerve: A two-case report

Plexiform neurofibroma is a benign peripheral nerve-sheath tumor, rarely involving major nerves of the extremities. In the literature, there are no clear treatment strategies for plexiform neurofibroma of major peripheral nerves. Our experience encountered two patients with plexiform neurofibroma of the median nerve, presenting with a palmar mass and symptoms of carpal tunnel compression. Preoperatively, plexiform neurofibroma was diagnosed on MRI and clinical examination. Both patients also experienced significant neurological deterioration, with finger numbness and increased nerve/tumor size. Potential malignant transformation was also considered. For these reasons, resection of the involved area of the nerve and repair were indicated. In both patients, intraoperative pathological diagnosis was plexiform neurofibroma. The 45-year-old male patient refused further surgery after carpal tunnel release, which was performed under axillary block. One year postoperatively, nerve compression symptoms decreased moderately. In the other patient, a 7-year-old boy, a significantly enlarged area of the median nerve was resected, and neurorrhaphy was performed. One year postoperatively, median nerve motor-sensory functions recovered completely. Four years postoperatively, no enlargement of the residual tumor was observed.

7T for clinical imaging of benign peripheral nerve tumors: preliminary results

PURPOSE

MRI has become an essential diagnostic imaging modality for peripheral nerve pathology. Early MR imaging for peripheral nerve depended on inferred nerve involvement by visualizing downstream effects such as denervation muscular atrophy; improvements in MRI technology have made possible direct visualization of the nerves. In this paper, we share our early clinical experience with 7T for benign neurogenic tumors.

MATERIALS

Patients with benign neurogenic tumors and 7T MRI examinations available were reviewed. Cases of individual benign peripheral nerve tumors were included to demonstrate 7T MRI imaging characteristics. All exams were performed on a 7T MRI MAGNETOM Terra using a 28-channel receive, single-channel transmit knee coil.

RESULTS

Five cases of four pathologies were selected from 38 patients to depict characteristic imaging features in different benign nerve tumors and lesions using 7T MRI.

CONCLUSION

The primary advantage of 7T over 3T is an increase in signal-to-noise ratio which allows higher in plane resolution so that the smallest neural structures can be seen and characterized. This improvement in MR imaging provides the opportunity for more accurate diagnosis and surgical planning in selected cases. As this technology continues to evolve for clinical purposes, we anticipate increasing applications and improved patient care using 7T MRI for the diagnosis of peripheral nerve masses.

What is new in intraneural perineurioma?

Since the initial description of intraneural (IN) perineurioma in 1964, advances in the understanding of the clinical presentation, diagnostic imaging, pathologic features, and genetic underpinnings have changed how this pathology is managed. IN perineuriomas are rare, benign peripheral nerve sheath tumors, most frequently coming to clinical attention when patients present with painless, progressive weakness or sensory loss in adolescence or young adulthood. The gold standard of diagnosis has traditionally been with targeted tissue biopsy demonstrating "pseudo-onion bulb" formation with positive epithelial membrane antigen (EMA) staining. However, modern magnetic resonance imaging is allowing some patients to forgo biopsy. Recent genetic studies of IN perineuriomas have demonstrated common TRAF7 point mutations and rare NF2 mutations, which may present targets for diagnosis or therapy in the future. Current advances have allowed for us to provide improved patient counseling with informed understanding for various clinical scenarios. With the workup and diagnosis now clearly defined, the next frontier is for improving the lives of patients with IN perineuriomas through the interaction between restoration of functional deficits and advances in our understanding of the genetics of this entity.

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.

Diagnostic Pathology of Tumors of Peripheral Nerve

Neoplasms of the peripheral nervous system represent a heterogenous group with a wide spectrum of morphological features and biological potential. They range from benign and curable by complete excision (schwannoma and soft tissue perineurioma) to benign but potentially aggressive at the local level (plexiform neurofibroma) to the highly malignant (malignant peripheral nerve sheath tumors [MPNST]). In this review, we discuss the diagnostic and pathologic features of common peripheral nerve sheath tumors, particularly those that may be encountered in the intracranial compartment or in the spine and paraspinal region. The discussion will cover schwannoma, neurofibroma, atypical neurofibromatous neoplasms of uncertain biological potential, intraneural and soft tissue perineurioma, hybrid nerve sheath tumors, MPNST, and the recently renamed enigmatic tumor, malignant melanotic nerve sheath tumor, formerly referred to as melanotic schwannoma. We also discuss the diagnostic relevance of these neoplasms to specific genetic and familial syndromes of nerve, including neurofibromatosis 1, neurofibromatosis 2, and schwannomatosis. In addition, we discuss updates in our understanding of the molecular alterations that represent key drivers of these neoplasms, including neurofibromatosis type 1 and type 2, SMARCB1, LZTR1, and PRKAR1A loss, as well as the acquisition of CDKN2A/B mutations and alterations in the polycomb repressor complex members (SUZ12 and EED) in the malignant progression to MPNST. In summary, this review covers practical aspects of pathologic diagnosis with updates relevant to neurosurgical practice.

[Synchronous schwannoma and ependymoma of the cauda equina]

The article presents a case of surgical treatment of primary multiple benign tumors of the cauda equine of different histological origin: spinal nerve root schwannoma and ependymoma of the filum terminale.

Imaging of non-neurogenic peripheral nerve malignancy-a case series and systematic review

OBJECTIVE

To evaluate the frequency, clinico-pathologic and imaging features of malignant tumors in peripheral nerves which are of non-neurogenic origin (non-neurogenic peripheral nerve malignancy-PNM).

MATERIALS AND METHODS

We retrospectively reviewed our pathology database for malignant peripheral nerve tumors from 07/2014-07/2019 and performed a systematic review. Exclusion criteria were malignant peripheral nerve sheath tumor (MPNST). Clinico-pathologic and imaging features, apparent diffusion coefficient (ADC_min), and standard uptake values (SUV_max) are reported.

RESULTS

After exclusion of all neurogenic tumors (benign = 196, MPNST = 57), our search yielded 19 non-neurogenic PNMs (7%, n = 19/272), due to primary intraneural malignancy (16%, n = 3/19) and secondary perineural invasion from an adjacent malignancy (16%, n = 3/19) or metastatic disease (63%, n = 12/19). Non-neurogenic PNMs were located in the lumbosacral plexus/sciatic nerves (47%, n = 9/19), brachial plexus (32%, n = 6/19), femoral nerve (5%, n = 1/19), tibial nerve (5%, n = 1/19), ulnar nerve (5%, n = 1/19), and radial nerve (5%, n = 1/19). On MRI (n = 14/19), non-neurogenic PNM tended to be small (< 5 cm, n = 10/14), isointense to muscle on T1-W (n = 14/14), hyperintense on T2-WI (n = 12/14), with enhancement (n = 12/12), low ADC_min (0.5-0.7 × 10-3 mm²/s), and variable metabolic activity (SUV_max range 2.1-13.1). A target sign was absent (n = 14/14) and fascicular sign was rarely present (n = 3/14). Systematic review revealed 89 cases of non-neurogenic PNM.

CONCLUSION

Non-neurogenic PNMs account for 7% of PNT in our series and occur due to metastases and primary intraneural malignancy. Although non-neurogenic PNMs exhibit a non-specific MRI appearance, they lack typical signs of neurogenic tumors such as the target sign. Quantitative imaging features identified by DWI (low ADC) and F¹⁸-FDG PET/CT (high SUV) may be helpful clues to the diagnosis.

Acute Neurologic Deterioration in Mobile Spinal Schwannoma

BACKGROUND

Spinal schwannomas are commonly presented with minor symptoms, including radicular pain, sensory deficits, and minor neurologic deficit. Acute neurologic deterioration is uncommon.

CASE DESCRIPTION

In this study, a case of cauda equina schwannoma presented with acute neurologic deficit after movement of spinal schwannoma is presented.

CONCLUSIONS

It is noted that movement of spinal schwannoma and resultant acute neurologic deterioration should be considered during the follow-up.

Posterior Microscopic and Anterior Robotic Assisted STAGED Approach for Voluminous "Dumbbell" Ganglioneuroma - Surgical Technique and Literature Review

Introduction: ganglioneuromas are benign tumors emerging from the sympathetic nervous system that could grow up to significant sizes before becoming symptomatic. Aim: to describe the surgical technique of the posterior microscopic and anterior robotic assisted staged approach for voluminous "dumbbell" ganglioneuroma. Besides this, a detailed report of the evolution of 9 years old female patient with such a tumor who underwent a staged bipolar approach, under direct neuromonitoring is presented. The literature has been reviewed on this topic. Methods: the neurosurgical approach consisted in S2-S3 laminectomy, resecting the intracanalar and intraforaminal S2 tumor, ligating and sectioning the S2 root, the surgical approach was minimally invasive using the DaVinci XI platform for excising the anterior retrorectal extension. Results: As for the posterior surgical stage, the neurosurgical operating time was 165 minutes with a five days hospital stay, and the second anterior surgical staged step took 660 minutes with five days hospital stay. There were no complications in both surgical stages, and the postoperative outcome was uneventful. The 6 months MRI evidenced no recurrency. Conclusions: the posterior microscopic and anterior robotic-assisted staged approach with continuous neuromonitoring for "dumbbell" ganglioneuroma has proven to be an efficient surgical strategy and technique. Further studies may support the effectiveness of this novel surgical approach and strategy.

Intracranial Mimics of Cauda Equina Syndrome: Heads or Tails?

BACKGROUND

To report cases of extraspinal mimics of cauda equina syndrome (CES) to enable prompt diagnosis and treatment in the future. CES results from compression of spinal nerve roots. Current practice mandates lumbosacral magnetic resonance imaging (MRI) scanning to diagnose CES. However, it may not reveal compression or provide an explanation for the presentation. We present 3 cases of suspected CES who went on to have intracranial pathology.

METHODS

Retrospective review of all patients presenting with CES-type features who were subsequently found to have causative intracranial pathology over a 6-month period.

RESULTS

Three cases were found, and these are hereby presented.

CASE PRESENTATION

Case 1: A 57-year-old lady presented with urinary retention and bilateral leg weakness. She underwent an MRI spine which showed no evidence of CES. She was diagnosed with haemorrhagic intracranial metastases. Case 2: A 52-year-old lady presented with lower back and right buttock pain, with right-sided leg numbness, saddle hypoesthesia, and bowel and bladder incontinence. MRI spine showed no cauda equina compression. MRI neuraxis revealed a subdural haematoma. Case 3: A 69-year-old lady presented with a 6-day history of urinary incontinence, right foot drop, and leg weakness. MRI spine was negative for CES. She was diagnosed with an intraparenchymal haematoma of posterior left frontal lobe.

CONCLUSIONS

Negative lumbosacral MRI will not exclude extraspinal mimics of CES and, although rare, these cases should be considered.

Radial neuropathy caused by intraneural leiomyoma: A case report

INTRODUCTION

Leiomyoma of peripheral nerve is a rare condition characterized by neuropathy of affected nerve. We herein report a rare presentation of leiomyoma of radial nerve which presented with wrist drop.

PATIENT CONCERNS

A 37-year-old man visited our clinic with a history of sudden onset weakness of the wrist dorsiflexion/finger extension of the right side.

DIAGNOSIS

T2-weighted with fat saturation image of MRI demonstrated a well-defined, intra-neural, round mass of about 0.8 cm × 0.5 cm within the radial nerve. Excision of mass established the pathological diagnosis of intra-neural leiomyoma.

INTERVENTIONS

The patient underwent excision of mass and attached nerve tissue, followed his medial antebrachial nerve graft for repair of the defected radial nerve.

OUTCOMES

As of the 1-year follow-up, no symptoms of recurrence have been observed. Also, the strength of wrist dorsiflexion improved to grade 4/5 CONCLUSION:: This rare case demonstrates the importance of MR imaging to differentiate intra-neural leiomyomas from other benign peripheral nerve sheath tumors. Surgical treatment plays an important role in the treatment of patient with intraneural leiomyoma with neurologic deficits.

C-Fiber Loss as a Possible Cause of Neuropathic Pain in Schwannomatosis

Schwannomatosis is the third form of neurofibromatosis and characterized by the occurrence of multiple schwannomas. The most prominent symptom is chronic pain. We aimed to test whether pain in schwannomatosis might be caused by small-fiber neuropathy. Twenty patients with schwannomatosis underwent neurological examination and nerve conduction studies. Levels of pain perception as well as anxiety and depression were assessed by established questionnaires. Quantitative sensory testing (QST) and laser-evoked potentials (LEP) were performed on patients and controls. Whole-body magnetic resonance imaging (wbMRI) and magnetic resonance neurography (MRN) were performed to quantify tumors and fascicular nerve lesions; skin biopsies were performed to determine intra-epidermal nerve fiber density (IENFD). All patients suffered from chronic pain without further neurological deficits. The questionnaires indicated neuropathic symptoms with significant impact on quality of life. Peripheral nerve tumors were detected in all patients by wbMRI. MRN showed additional multiple fascicular nerve lesions in 16/18 patients. LEP showed significant faster latencies compared to normal controls. Finally, IENFD was significantly reduced in 13/14 patients. Our study therefore indicates the presence of small-fiber neuropathy, predominantly of unmyelinated C-fibers. Fascicular nerve lesions are characteristic disease features that are associated with faster LEP latencies and decreased IENFD. Together these methods may facilitate differential diagnosis of schwannomatosis.

Clinical and radiological characteristics of 82 solitary benign peripheral nerve tumours

Benign peripheral nerve tumours are rare lesions. The surgical treatment and clinical outcomes depend on the resectability. The aim of this retrospective study was to identify clinical or radiological features that may predict the surgical technique that should be used to improve clinical outcome. Eighty-two patients were diagnosed with solitary benign peripheral nerve tumours. Fifty-five tumours were surgically resectable, and 27 were nonresectable. Pre-operative magnetic resonance imaging and ultrasound were used, which were predictive of the neural origin of the tumours in 87% (39/45) of cases imaged. In 78% (50/64) of cases imaged, an origin from the nerve sheath (peripheral nerve sheath tumour), or from non-neural elements was possible. However, no imaging or clinical criteria were identified that could determine tumour resectability preoperatively. The diagnosis of solitary peripheral nerve tumour still relies on the macroscopic appearance and definitive histology after epineurotomy.

Brachial Plexus Schwannoma: A Case Report with Emphasis on Imaging

Brachial plexus tumors are rare. Schwannomas are benign nerve sheath tumors and only about 5% arise from brachial plexus. Diagnosis of these tumors are challenging for radiologists as well as clinicians as they are rare and the anatomy of the neck is complex. We report a case of a middle aged woman who was admitted in Mymensingh Medical College in Neurosurgery Department on 15th December 2017 with right supraclavicular swelling; based on the clinical findings was provisionally diagnosed as supraclavicular lymphadenopathy; Ultrasonography and Magnetic Resonance Imaging suggested schwannoma. Complete excision of the mass through supraclavicular approach showed the origin of it from the brachial plexus, which subsequently was confirmed to be a schwannoma with histopathology.

Division of Sacrospinous and Sacrotuberous Ligaments Expands Access Through Greater Sciatic Foramen: Anatomic Study with Application to Resection of Greater Sciatic Foramen Tumors

OBJECTIVE

Tumors of the greater sciatic foramen remain difficult to treat. They often have both intrapelvic and extrapelvic components that may limit visualization and make safe resection of the tumor difficult. Therefore the goal of the present anatomic study was to quantitate how much additional surgical working space could be gained by transection of the sacrospinous and sacrotuberous ligaments.

METHODS

Sixteen sides from 9 fresh-frozen Caucasian cadaveric torsos underwent transgluteal dissection and exposure of the greater sciatic foramen and associated liagments. With the piriformis in place, the vertical and horizontal diameters of the greater sciatic foramen were measured. Next, the sacrotuberous and sacrospinous ligaments were cut at their ischial attachments. The vertical diameter of the now confluent greater and lesser sciatic foramina (V₂) was measured.

RESULTS

The mean vertical diameter of the greater sciatic foramen (V₁) was 54.8 ± 9.7 mm. The horizontal diameter of the greater sciatic foramen had a mean of 44.3 ± 6.1 mm with a range of 30-52 mm. After transection of the sacrotuberous and sacrospinous ligaments, the vertical distance of the greater and lesser sciatic foramina (V₂) had a mean of 74.8 ± 6.8 mm with a range of 60.1-90 mm. The mean ratio of V₂ to V₁ was 1.40.

CONCLUSIONS

The vertical length of the greater sciatic foramen increased, on average, 40% after resection of the sacrotuberous and sacrospinous ligaments. The results of this study support an alternative technique for resecting large intrapelvic tumors via a transgluteal approach.

Superficial peroneal nerve schwannoma presenting as lumbar radicular syndrome in a non-competitive runner

INTRODUCTION

Running is one of the most common sports practices in the world due to the beneficial impact on the health, despite the relatively high risk of getting injuries. In fact, running is one of the most common sports capable to induce overuse injuries of the lower back and leg. In previous studies, the symptoms in the lower limb have been attributed to lumbosacral degenerative pathology. When the symptoms are unclear, they must be studied with great attention by carrying out an accurate process of screening and differential diagnosis.

MATERIALS AND METHODS

A 42-year-old non-competitive male runner who complained of left leg pain was referred to a physiotherapist. He reported a continuous, deep, sharp, shooting pain of the left leg. The symptoms began one year earlier. Symptoms worsened during prolonged driving and long distance running. The patient had been previously diagnosed with lumbar radicular irradiation in the leg by a general practitioner. Initial management, in another physical therapy outpatient setting, was without any improvement.

RESULTS

After surgical excision, symptoms gradually regressed shortly and the patient was referred to a physiotherapist in order to fully recover and restore work and running activities.

CONCLUSION

This case report describes the history, assessment and treatment of a runner with a rare cause of leg pain. After surgery excision, treatment focused on education and loading the tissues over many weeks through a graded program of loaded exercises and running retraining.

Image Possibilities of the Peripheral Nerve Tumor Using Magnetic Resonance Imaging - Case Report

Magnetic resonance imaging (MRI) plays a crucial role in the diagnosis and morphological analysis of peripheral nerve tumours (PNTs). In recent years, a number of novel MRI sequences such as MR neurography (MRN), diffusion tensor imaging (DTI) or MR tractography (MRT) have emerged extending the range of conventional MRI techniques. These advanced sequences are able to provide detailed information concerning PNTs structure, including the course and function of individual neural fascicles. This data can then be utilized in tailoring a suitable surgical procedure, reducing the risks of postoperative neurological deficit. The following case report of a median nerve tumour demonstrates the range and practicality of current MRI techniques. With continuing advancement and perfection of these MRI techniques, we can expect their integration into standard diagnostic protocols of PNTs.

Brachial plexus schwannoma mimicking cervical lymphadenopathy: A case report with emphasis on imaging features

RATIONALE

Brachial plexus schwannomas are rare benign tumors that are derived from Schwann cells. Because they are rare, and because of the complexity of the anatomy of the neck, these tumors can be a challenge to diagnose for radiologists and clinicians. In the present study, we describe a clinical case of brachial plexus schwannoma detected on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI), and presenting as a palpable neck mass.

PATIENT CONCERNS

A 49-year-old woman had a palpable mass in the right neck, which had been there for the last 1 year. Metastatic cervical lymphadenopathy was suspected in the primary health clinic; therefore, the patient was referred to our hospital.

DIAGNOSES

The right neck mass was a well-circumscribed oval soft tissue mass on US, CT, and MRI. US-guided core needle biopsy was performed and the mass was proved to be a schwannoma.

INTERVENTIONS

The patient did not undergo surgical excision because the brachial plexus schwannoma was small and there was no accompanying neurological symptom.

OUTCOMES

The patient is being followed up regularly at the outpatient department.

LESSONS

Brachial plexus schwannoma should be considered for a differential diagnosis in patients with a palpable neck mass, and imaging studies play an important role in diagnosing the brachial plexus schwannoma.

Analysis of Peripheral Nerve Schwannoma Pseudocapsule

BACKGROUND

Using proper surgical technique, schwannomas can be resected safely, with a low recurrence rate and high likelihood of improvement in symptomatology. There are multiple peritumoral tissue layers, and finding the correct plane is critical to safe tumor enucleation. The contents of the pseudocapsule tissue surrounding a schwannoma are not well described, and the consequences of resecting or leaving pseudocapsules are unknown.

METHODS

An institutional database was searched for any pathology reports that contained both of the words "schwannoma" and "capsule." Charts and histopathologic specimens were reviewed to determine the contents of various tissue layers and determine if there was any correlation between pseudocapsular contents and clinical outcomes.

RESULTS

A pseudocapsule was separately sent for pathology in 36 patients during schwannoma resection. Ten pseudocapsule specimens contained microscopic foci of tumor. In a separate 6 patients, there was evidence of nerve fascicles. There were no correlations between the tumor or nerve in the pseudocapsule and postoperative neurologic deficits. After an average follow-up time of 3.1 years, no patients developed a recurrence either clinically or on follow-up imaging (imaging available in 52.7%). Histopathologically, the pseudocapsule was made of dense hypocellular collagen and occasionally contained arteries, veins, and nerve fascicles.

CONCLUSIONS

The pseudocapsule surrounding a schwannoma occasionally contained nerve tissue and blood vessels. While a microscopic focus of tumor was often found in this tissue layer, recurrence is exceedingly rare and did not occur in this case series. The risk of undue pseudocapsule dissection likely outweighs any negligible benefit from microscopic cytoreduction.

Extrapancreatic perineural invasion in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma continues to be a highly lethal disease, despite advances in modern medicine. Curative surgical options continue to carry significant morbidity and offer little improvement in overall 5-year survival. Currently, imaging plays an essential role in the pre-operative evaluation of patients who are undergoing evaluation for resection. However, some pancreatic cancers have particularly aggressive biology, despite appearing resectable by conventional imaging criteria. Imaging biomarkers that serve as surrogates for tumors with such aggressive phenotype have been recently described, namely duodenal invasion and extrapancreatic perineural invasion. In this pictorial review, we will summarize key concepts of extrapancreatic perineural invasion, describe its association with a poor prognosis, and highlight the role of imaging in its detection.

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.].

Six cases of sporadic schwannomatosis: Topographic distribution and outcomes of peripheral nerve tumors

The diagnosis of schwannomatosis is often overestimated and is based on the existence of multiple peripheral nerve tumors composed exclusively of schwannomas, in the absence of clinical signs of neurofibromatosis type 2 (NF2). Sporadic forms are much more frequent than familial forms. The objective of this study was to describe the distribution of peripheral nerve tumors and investigate the outcomes of schwannomas in the context of sporadic schwannomatosis. We conducted a retrospective study of patients who fulfilled clinical diagnostic criteria for sporadic schwannomatosis. Six patients were reviewed with a mean follow-up of 38.5months (27-60months). Patients' demographic, clinical, radiographic, and pathologic data were extracted. All patients underwent slit-lamp examination, enhanced brain magnetic resonance imaging (MRI) and a spinal MRI. Enucleation that preserved nerve continuity was performed in symptomatic patients. On average, patients were 36years of age at the time of diagnosis with no sex predominance. The topographic distribution of the peripheral nerve tumors was always unilateral and most frequently targeted the upper limb. In four cases, the tumors involved the same peripheral nerve exclusively. The average number of nerve tumors observed per patient was 4.7 (2-8). The outcome after enucleation was marked by the systematic appearance of new tumors. After enucleation, no recurrence or malignant transformation was observed at the final follow-up. There was no transition to a NF2 configuration. The absence of neurofibroma and NF2 criteria makes schwannomatosis a diagnosis of exclusion. While a good prognosis can be expected following enucleation, two risks related to neurofibromatosis type 3 (NF3) are worth monitoring: the transition to NF2, particularly in young patients, and the appearance of new tumors.

High-resolution ultrasonography and shear-wave sonoelastography of a cystic radial nerve Schwannoma

Peripheral nerve tumors are often evaluated with magnetic resonance imaging (MRI), although there are many advantages offered with high-resolution ultrasonography (HRUS). This case report emphasizes the value of HRUS in the diagnosis and management of a patient with a cystic radial nerve Schwannoma. In addition, information on tumor stiffness, obtained with shear-wave sonoelastography (SWE), is presented.

Ultrasound Imaging for Posterior Knee Pain: Tibial Nerve Schwannoma Not Popliteus Muscle Strain

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[Hourglass neurinoma resulted in symptoms of polyneuropathy]

Distal symmetric polyneuropathy (DSP) is a common condition where limited diagnostic evaluation is usually required. We present a case story of a 50-year-old male who had symptoms of DSP, but electrodiagnostic testing suggested a more proximal lesion, and magnetic resonance imaging showed a spinal nerve root schwannoma. The patient recovered completely after surgery. This case exemplifies relevant use of electrodiagnostic testing. Based on a recent review, we briefly mention atypical features which should prompt further testing, emphasizing that evaluation should be reserved to a limited group of patients.

Schwannoma of the median nerve mimicking carpal tunnel syndrome in a pregnant patient. Case report

In patients with symptoms of a peripheral neuropathy especially during pregnancy, use of imaging techniques such as Ultrasound (US) and Magnetic Resonance Imaging (MRI) may be essential for the diagnostic accomplishment. A 30-weekspregnant diabetic female attending US evaluation due to intermittent hand pain, numbness, and weakness bilaterally. Although, the US evaluation revealed the median nerve (MN) normal size, echogenicity and echo-texture within the right carpal tunnel; the US assessment applied proximally to the carpal tunnel, revealed a hypoechoic tumor-like mass and increased MN cross section area. In transverse view, the MN was detected as an eccentric, hypoechoic structure compressed by the aforementioned mass. A presence of MN schwannoma or neurofibroma was suspected. US has been proved to be extremely useful to determine location, extent as well as the type of nerve lesion.

Giant Schwannoma of the Saphenous Nerve in The Distal Thigh: A Case Report

CASE

Schwannomas are benign nerve myelin sheath tumors that can occur anywhere in the peripheral nervous system. It is very rare for Schwannomas to become malignant, but surgery is still the principal treatment to eliminate symptoms and to correctly diagnosis the tumor. We report an interesting case of a schwannoma of the saphenous nerve at the distal third of the posteromedial thigh: the patient complained of muscle weakness at left lower limb and vague anteromedial knee pain, mimicking a meniscal tear. Magnetic resonance images of the thigh showed a well-defined and oval mass lesion measuring 8.5 cm x 4.5 cm. Before investigating for a possible meniscal tear, we decided to remove the mass from the thigh, because we felt that it could itself be the cause of the mild pain complained about by the patient. Post-surgery, histological analysis conducted confirmed that this was a benign schwannoma.

DISCUSSION

Schwannomas generally can be asymptomatic or present as a mass. The clinical presentation of this rare tumor makes the diagnosis difficult.

CONCLUSION

This reported case is particularly interesting because of the rarity of the lesion localization along the course of the saphenous nerve. The combination of the location, and especially the large size of the tumor, led us to believe that there is a correlation with the particular clinical presentation.

Sonographic Differentiation Between Schwannomas and Neurofibromas in the Musculoskeletal System

OBJECTIVES

The purpose of this study was to determine key features and define a strategy for differentiation between schwannomas and neurofibromas using sonography.

METHODS

This retrospective study was approved by the Institutional Review Board at our hospital, and informed consent was waived. We reviewed sonograms of pathologically proven schwannomas and neurofibromas of the extremities and body wall. On grayscale images, tumors were evaluated on the basis of their size, maximum-to-minimum diameter ratio, shape, contour, margin, location, encapsulation, echogenicity, echo texture, cystic changes, presence of intratumoral calcifications, presence of a target sign, and presence of an entering or exiting nerve. If an entering or exiting nerve was identified, the nerve-tumor position and nerve-tumor transition were characterized. On color Doppler images, the presence and amount of vascularity were evaluated. Student t tests were used for analysis of continuous variables (size, maximum-to-minimum diameter ratio, and age); χ(2) and Fisher exact tests were used for analysis of categorical variables.

RESULTS

A total of 146 pathologically proven tumors, including 115 schwannomas and 31 neurofibromas of the extremities and body wall, were included. The maximum diameter, maximum-to-minimum diameter ratio, contour, cystic portion, nerve-tumor position, nerve-tumor transition, and vascularity were significantly different in schwannomas versus neurofibromas (P < .05), and a lobulated contour, fusiform shape, and hypovascularity of neurofibromas could be helpful for differentiation when a prediction model is considered. The nerve-tumor position, nerve-tumor transition, and maximum-to-minimum diameter ratio were also significantly different between groups (P < .05) and thus could be useful for differentiation of neurogenic tumors.

CONCLUSIONS

Sonographic findings are helpful in differentiating between schwannomas and neurofibromas.

Percutaneous Ultrasound-Guided Hydrodissection of a Symptomatic Sural Neuroma

Symptomatic neuromas of the sural nerve are a rare but significant cause of pain and debilitation in athletes. Presentation is usually in the form of chronic pain and dysesthesias or paresthesias of the lateral foot and ankle. Treatment traditionally ranges from conservative measures, such as removing all external compressive forces, to administration of nonsteroidal anti-inflammatory drugs, vitamin B6, tricyclic antidepressants, antiepileptics, or topical anesthetics. This article reports a case of sural nerve entrapment in a 34-year-old male triathlete with a history of recurrent training-induced right-sided gastrocnemius strains. The patient presented with numbness in the right lateral foot and ankle that had persisted for 3 months, after he was treated unsuccessfully with extensive nonoperative measures, including anti-inflammatory drugs, activity modification, and a dedicated physical therapy program of stretching and strengthening. Orthopedic assessment showed worsening pain with forced passive dorsiflexion and manual pressure applied over the distal aspect of the gastrocnemius. Plain radiographs showed normal findings, but in-office ultrasound imaging showed evidence of sural nerve entrapment with edema and neuromatous scar formation in the absence of gastrocnemius or soleus pathology. Percutaneous ultrasound-guided hydrodissection of the sural nerve at the area of symptomatic neuroma and neural edema was performed the same day. The patient had complete relief of symptoms and full return to the preinjury level of participation in competitive sports. This case report shows that hydrodissection, when performed by an experienced physician, can be an effective, minimally invasive technique for neurolysis in the setting of sural nerve entrapment, resulting in improvement in clinical symptoms.

High-Resolution Ultrasound for Diagnostic Assessment of the Great Auricular Nerve--Normal and First Pathologic Findings

PURPOSE

The great auricular nerve (GAN) is a sensory branch of the superficial cervical plexus. While its blockade is an established procedure, little is known about the ultrasound appearance of pathologic conditions of the GAN itself. We, therefore, aimed to evaluate the possibility of the visualization and diagnostic assessment of the GAN along its entire course by means of high-resolution ultrasound (HRUS).

MATERIALS AND METHODS

To assess the feasibility of visualization, we performed HRUS with an 18 MHz probe, HRUS-guided, fine-needle ink markings and consecutive dissection in six anatomical specimens. Then, we measured the diameter of the GAN in healthy volunteers and finally performed a retrospective review of patients referred for HRUS examinations because of pain within GAN territory between August 1, 2012 and August 1, 2013.

RESULTS

The GAN was clearly visible with HRUS from its formation to the final branches, and was marked successfully on both sides in all anatomical specimens (n = 12). The mean average in-vivo was 0.14 cm ± 0.03 (range 0.08-0.2). Seven cases of patients with GAN pathologies of various origins (idiopathic, traumatic, tumorous and iatrogenic) were identified, of which 6 were visible on HRUS and all of which could be confirmed by complete resolution of symptoms after selective HRUS-guided GAN block.

CONCLUSION

This study confirms the reliable ability to visualize the GAN with HRUS throughout its course, both in anatomical specimens and in vivo. The provided cases show that pathologies of the GAN seem to have a variety of causes and may not be rare. We, therefore, encourage the use of HRUS in patients with unclear pain in the auricular, periauricular and posterior-lateral head.

Diagnosis of closed injury and neoplasm of the brachial plexus by ultrasonography

PURPOSE

To evaluate the feasibility and accuracy of high-frequency sonography (US) in diagnosing traumatic brachial plexus (BP) lesions and neoplasms in the adult.

METHODS

Eleven patients with suspected BP closed trauma, 6 patients with BP neoplasm, and 12 healthy volunteers were scanned. The US findings were compared with surgical findings.

RESULTS

The interscalene space and intervertebral foramina were useful anatomic markers in identifying the BP. In the 24 sites examined in the normal group (12 subjects examined on both sides), the fifth to seventh cervical nerve roots (C5-7, including upper and middle trunk) were seen, whereas the eighth cervical and first thoracic nerve roots (C8, T1, including the lower trunk) were seen in 91.7% (22/24) of the subjects. The BP appeared as three or four discrete rounded hypoechoic nodules between the anterior scalene and middle scalene muscle in transverse views at the C5-7 level, representing the trunks in the sagittal oblique section. In the BP trauma group (n = 11), the normal nerve trunk was interrupted, and lesions were shown as thickening and swelling with indistinct inner structures. In the neoplasm group (n = 6), masses were shown as hypoechoic masses.

CONCLUSIONS

High-frequency US is valuable in diagnosing BP closed injuries and neoplasms.

Ultrasound imaging of the axillary nerve and its role in the diagnosis of traumatic impairment

PURPOSE

The axillary nerve (AN) is frequently injured during shoulder trauma and imaging is required to define the site and extent of nerve injury. However, the AN has a rather complex course through several soft tissue compartments of the shoulder and axilla. Therefore, imaging of the nerve with MRI and sonography is troublesome. Thus detection and sonographic assessment bases on thorough knowledge of local topography.

MATERIALS AND METHODS

This investigation aimed at defining reliable anatomical landmarks for AN-sonography in 5 volunteers and later validating the proposed sonographic examination protocol in 10 unselected patients.

RESULTS

With strict adherence to the proposed examination algorithm, sonography of the AN was feasible in all volunteers and patients. Furthermore, sonographic findings correlated nicely with the golden standard "surgical exploration" concerning severity and topography of neural impairment.

CONCLUSION

Based on our study results we propose our algorithm for AN-sonography as the first-line imaging tool for the assessment of axillary nerve trauma.

Ancient schwannoma of vagus nerve mimicking hamartoma

Schwannomas arising from vagus nerve sheath are rare mediastinal neurogenic tumours. Schwannomas usually arise from left hemithorax. Unlike a hamartoma, radiologically, calcification is rarely seen in schwannomas. We present the rare case of an ancient schwannoma arising from vagus nerve sheath from the right hemithorax presenting with gross calcification.

High-resolution ultrasonography for the diagnosis of brachial plexus root lesions

The aim of this study was to investigate the feasibility of using high-resolution ultrasonography in the diagnosis of brachial plexus (BP) root lesions. A prospective study of ultrasonographic evaluation of BP nerve roots was performed in 37 patients with BP root lesions (29 with root injuries, 8 with tumors). The pre-operative ultrasonographic findings were compared with the surgical and pathohistological findings. All C5-7 roots were detected by ultrasonography in all patients, whereas 92% (68/74) of C8 and 51% (38/74) of T1 nerve roots were visualized. Among 29 patients with BP root avulsion, partial injuries or totally interrupted BP roots were detected in all patients. Cystic masses and neuromas were detected in 16 and 23 patients, respectively. In 8 patients with BP root tumors, 8 hypo-echoic masses were detected inside or partly outside of intervertebral foramina connecting to nerve roots. Surgical exploration revealed that there were 57 BP root avulsions in 29 patients. However, 2 T1 nerve root avulsions had been missed by pre-operative ultrasonography. Pathohistology revealed that all 8 BP root tumors pre-operatively diagnosed by ultrasonography were schwannomas. High-resolution ultrasonography can provide a convenient and accurate imaging modality for quick diagnosis and location of BP root lesions.

A relapsing macrodactyly

Lipofibromatous hamartoma is an uncommon benign tumor, usually unknown or misdiagnosed. We report the case of a 61-year-old patient presenting an acquired painful macrodactyly of the left thumb with paresthesia in the median nerve territory. Clinical examination reveals a tumefaction of the volar side of the wrist. She had a medical history of amputation of the forefinger for macrodactyly without any diagnosis. Paraclinical exploration guided us to the correct diagnosis; hypertrophic bone structures of the affected finger were detected on radiographs. The left median nerve appeared hypertrophic, with a fatty infiltration on the ultrasound exploration. These pathological findings revealed a late discovered lipofibromatous hamartoma of the median nerve, a rare entity often associated with macrodactyly and diagnosed in childhood. Therefore, we retrospectively made the same diagnosis for the amputated index finger with the analysis of her ancient paraclinical exams. Lipofibromatous hamartoma remains an obscure pathology and its treatment stays controversial.

Schwannoma of the nasal septum: an unusual finding

Schwannomas of the nasal cavity are rare benign tumors, and those that arise from the nasal septum are even rarer. When they do occur, they usually become symptomatic early because of the close confines of the nasal cavity. We describe a case of nasal septal schwannoma that was noteworthy in that the patient-a 28-year-old woman-waited 8 months after the onset of symptoms to seek medical care. Her symptoms included complete right-sided nasal obstruction, occasional epistaxis, and hemifacial pain. The tumor was completely removed via an endoscopic approach. We discuss the clinical presentation, differential diagnosis, and treatment of this rarely encountered neoplasm.

Unusual median nerve schwannoma: a case presentation

Peripheral nerve sheath tumors are common soft tissue neoplasms and their characterization is often challenging. Although the surgical pathology defines some typical entities, some degree of controversy regarding the classification of these tumors still exists. Newer imagistic and histopathological techniques are crucial for their accurate diagnosis and grading. We present an unusual case of median nerve schwannoma in a young patient, discussing the clinical, surgical and pathological elements, including immunohistochemistry.

Nuclear medicine and multimodality imaging of pediatric neuroblastoma

Neuroblastoma is an embryonic tumor of the peripheral sympathetic nervous system and is metastatic or high risk for relapse in nearly 50% of cases. Therefore, exact staging with radiological and nuclear medicine imaging methods is crucial for defining the adequate therapeutic choice. Tumor cells express the norepinephrine transporter, which makes metaiodobenzylguanidine (MIBG), an analogue of norepinephrine, an ideal tumor specific agent for imaging. MIBG imaging has several disadvantages, such as limited spatial resolution, limited sensitivity in small lesions and the need for two or even more acquisition sessions. Most of these limitations can be overcome with positron emission tomography (PET) using [F-18]2-fluoro-2-deoxyglucose [FDG]. Furthermore, new tracers, such as fluorodopa or somatostatin receptor agonists, have been tested for imaging neuroblastoma recently. However, MIBG scintigraphy and PET alone are not sufficient for operative or biopsy planning. In this regard, a combination with morphological imaging is indispensable. This article will discuss strategies for primary and follow-up diagnosis in neuroblastoma using different nuclear medicine and radiological imaging methods as well as multimodality imaging.