Benign Peripheral Nerve Tumors Research Articles

A rare clinical manifestation of plexiform neurofibroma in the absence of neurofibromatosis-1: a case report

Plexiform neurofibroma is a benign tumor of peripheral nerves that occurs in up to 30% of patients with neurofibromatosis type-1 (NF-1). We present a case of a 15-year-old male patient without NF-1, with an 11-year history of a slow growing, painless mass on the left side of the back extending to the gluteal region, with no constitutional symptoms but with some scoliosis. Histology of the mass was compatible with a plexiform neurofibroma. Plexiform neurofibromas commonly occur in, but are not limited to the craniofacial region. The mainstay of treatment is surgical resection, but complete resectability is challenging due to their locally infiltrative growth pattern. This highlights the need for patient-specific management strategies, even when established guidelines are in place.

A neuromuscular clinician's guide to magnetic resonance neurography.

Magnetic resonance neurography (MRN) is increasingly used in clinical practice for the evaluation of patients with a wide spectrum of peripheral nerve disorders. This review article discusses the technical aspects of MRN highlighting the core sequences performed for clinical care. A robust, high-resolution, heavily T2-weighted fluid-sensitive sequence performed on a 3.0 Tesla magnet system remains the main workhorse MRN sequence. In specific clinical scenarios, adjunct techniques such as diffusion-weighted imaging can be added to a protocol for disease characterization. In addition, gadolinium-based contrast material can also be administered for the purposes of image optimization (suppress adjacent vascular signal) and disease characterization. Technical modifications to field of view and planes of imaging can be made based on the clinical question and discussion with the radiologist(s). On fluid-sensitive MRN sequences, a normal peripheral nerve exhibits iso- to minimally hyperintense signal relative to skeletal muscle with a predictable trajectory, preserved "fascicular" architecture, and tapered caliber from proximal to distal. Peripheral nerve abnormalities on MRN include alterations in signal, caliber, architecture, diffusion characteristics as well as enhancement and provide information regarding the underlying etiology. Although some MRN findings including nerve hyperintensity and long-segmental enlargement are nonspecific, there are certain diagnoses that can be made with high certainty based on imaging including benign peripheral nerve tumors, high-grade peripheral nerve injury, and intraneural ganglia. The purpose of this article is to familiarize a neuromuscular clinician with fundamentals of MRN acquisition and interpretation to facilitate communication with the neuromuscular radiologist and optimize patient care.

A Rare Case of Retroperitoneal Schwannoma in an Adult Male

Objective. This study aims to illustrate a rare case of retroperitoneal schwannoma by presenting the clinical, imaging, and histological parameters. Case Report. A 36-year-old patient visited the outpatient clinic because of back pain experienced over the previous two months. There were no complaints regarding the nervous system or urinary system. Thorough imaging evaluation, including magnetic resonance for the lumbar spine, abdominal computed tomography, and positron emission tomography was conducted. An encapsulated mass was found in the retroperitoneal area, positioned in front of the O4 vertebra and in close proximity to the left psoas muscle, the left common iliac artery, and the left ureter. The lesion exhibited FDG radioisotope uptake, and a CT-guided biopsy confirmed a benign peripheral nerve tumor. The patient underwent laparotomy surgery, where the tumor was removed. The histological investigation, along with immunohistochemistry, confirmed the presence of a retroperitoneal schwannoma. Conclusion. Schwannoma is a rare type of retroperitoneal tumor, with nonspecific clinical and radiological characteristics that make diagnosis difficult. Surgical resection is the primary treatment for symptomatic patients, with a favorable prognosis. Long-term follow-up is advised to reduce the chance of late recurrence.

Collection of Rare Peripheral Nerve Tumors-Insights from the German Registry.

The most common peripheral nerve tumors are of a benign nature and include schwannoma or neurofibroma. In rare cases, other tumors or non-tumorous lesions can mimic peripheral nerve tumors clinically or radiologically. Based on data from the multicentric German Peripheral Nerve Tumor Registry (PNTR), which encompasses current information on 315 surgically treated patients from three high-volume centers, we present 61 cases of rare tumors and lesions that mimic tumors associated with peripheral nerves. This cohort displays considerable heterogeneity, featuring a broad spectrum of morphological features and biological potentials. Histopathological diagnoses include various intrinsic peripheral nerve tumors such as malignant peripheral nerve tumors (MPNSTs) (n = 13), perineurioma (n = 17), and hybrid nerve sheath tumors (HPNSTs, comprising schwannoma/perineurioma and schwannoma/neurofibroma) (n = 14), as well as atypical neurofibromatous neoplasm with unknown biological potential (ANNUBP) (n = 1). Additionally, the cohort encompasses extrinsic tumorous lesions like lymphoma (n = 3), lymphangioma (n = 2), hemangioma (n = 2), solitary fibrous tumor (n = 2), metastatic disease (n = 1), and single cases of other rare tumor entities (n = 6). An overview of the underlying pathology, imaging features, and clinical presentation is provided, with a brief description of each entity. A definitive preoperative differentiation between benign peripheral nerve tumors and rare intrinsic and extrinsic tumors is often not possible. Clinical examination and subtle imaging clues can at least indicate the possibility of a rare entity. The basic requirement is close cooperation between radiologists, neurologists, neuropathologists, and neurosurgeons at a specialized center to develop a multidisciplinary concept and offer the patient the best therapeutic approaches.

Schwannoma masquerading as a thyroid nodule: A diagnostic delimma.

We present a case of a 70 years old female presenting with a long-standing neck swelling with a recent increase in size and new onset pain. It was initially diagnosed and operated on as a cold nodule of thyroid as her thyroid scan showed left cold nodule and FNAC was inconclusive. However, a final diagnosis of schwannoma with Antoni A structures was made on histopathological attributes. Schwannomas are benign peripheral nerve tumors which grow slowly on parent nerves. The mainstay of treatment is surgical excision. To avoid unnecessary or inappropriate interventions, thorough pre-operative assessment is required in case of thyroid or non-thyroidal lesions as most are hypoechogenic on ultrasonography and fine needle aspiration has low diagnostic yield. The key pre-operative investigations are ultrasound and ultrasound guided cytology and immunohistochemical staining (for example S-100, calcitonin, CEA, thyroglobulin, TTF-1, melan-A, HMB45 and Ki-67). MRI is also a good diagnostic tool in neck swellings where diagnosis is uncertain.

Schwannomas: Experience from a single center reference in Peru.

e14043 Background: Schwannomas are nerve sheath tumors that originate in Schwann cells. They are usually solitary and sporadic and manifest on peripheral, spinal or cranial nerves. It is the most common type of benign peripheral nerve tumor in adults. These tumors represent a diagnostic challenge due to their rarity and difficult differential diagnosis. Our objective was to determine the clinical and pathological characteristics, as well as the therapeutic management of patients with Schwannoma admitted to our institution over a period of time. Methods: A retrospective, cross-sectional and descriptive study was carried out on the cases of patients with Schwannoma over 14 years of age, diagnosed at the National Institute of Neoplastic Diseases from 2009 to 2023. Medical records and pathology reports were reviewed. Results: A total of 225 patients were diagnosed with schwannoma on anatomopathology. Median age was 44 years, with a range of 15 to 92 years. 135 (60%) patients were female and 90 (40%) male, with a ratio of 1.5:1. 19 (8.4%) patients had a second cancer before or after the diagnosis of schwannoma. 6 (2.66%) patients were previously diagnosed with neurofibromatosis. According to anatomical origin: 27 (12%) patients had schwanommas of the abdominal region, 36 (16%) of the head and neck, 42 (18.66%) of the spinal cord, 17 (7.55%) of the extremities, 83 ( 36.88%) of the intracranial region and 20 (8.88%) of the thorax. At the intracranial level, 71 patients had location at the cerebellopontine angle, 5 at the orbital level, 2 at the level of the cerebellum and 5 in another location. At the abdominal level, 13 patients had a retroperitoneal location, 8 at the gastric level, 2 at the renal level and 4 in another location. In 130 patients we can obtain the ki67, median score was 2% (1-50%). Regarding treatment, 156 (69.33%) patients underwent surgery, and 42 (18.66%) patients received radiation treatment. During their follow-up, only 5 (2.22%) patients had local recurrence. Conclusions: Schwannomas are rare benign tumors. In many cases, its suspected diagnosis is difficult due to its similarity to other tumors that must be part of the differential diagnosis. Its treatment is surgical, with the objective of complete macroscopic resection. Radiotherapy is a complementary treatment in case of residual disease.

Health-related quality of life in patients with peripheral nerve tumors: results from the German multicentric Peripheral Nerve Tumor Registry.

Peripheral nerve tumors (PNTs) are rare diseases. So far, no multicenter data on diagnostics, the efficacy of treatment, long-term outcomes, and health-related quality of life (HRQoL) exist. The establishment of the Peripheral Nerve Tumor Registry (PNTR) in 2015 allows for the systematic analysis of patients with tumors associated with peripheral nerves. The present study aims to investigate the impact of PNT on an individual's HRQoL and the effect of surgery. HRQoL was pre- and postoperatively assessed by the Euro-Qol-5D-5L (EQ-5D-5L) and Euro-Qol visual analog scale (EQ-VAS) survey in the retrospective and prospective study arm in three active participating study centers. An index was calculated based on the EQ-5D-5L for the quantification of health state (0: worst possible state of health, 1: best possible state of health). The EQ-VAS ranges from 0% (worst imaginable health status) to 100% (best possible health status). Patient characteristics (age, sex), as well as disease (histopathological entity) and treatment (pre- and postoperative symptoms, type of treatment)-specific data, were analyzed. Data from 171 patients from three high-volume centers were included, with schwannoma (70.8%, n = 121) and neurofibroma (15.8%, n = 27) being the most prevalent histopathological diagnoses. Both the median health index value (preoperative: 0.887, n = 167; postoperative: 0.910, n = 166) and the median EQ-VAS (preoperative: 75%, n = 167; postoperative: 85%, n = 166) of the entire cohort regarding all histopathological diagnosis improved significantly after surgical therapy (p < 0.001). Preoperatively, 12.3% (n = 21) reached the highest index score of 1.0 in EQ-5D-5L and 100% in the EQ-VAS score in 5.3% (n = 9) of all patients. Postoperatively, the highest index score of 1.0 and 100% in the EQ-VAS score increased significantly and were achieved in 33.3% (n = 57) and 11.1% (n = 19) of the patients, respectively (p < 0.001). For the first time, our study presents multicenter data on life quality and the effect of surgery in primarily benign peripheral nerve tumors. Early surgery at a specialized center could improve neurological outcomes and, in conclusion, better QoL. In summary, surgical therapy significantly improved the entire cohort's QoL, VAS, and analgesia.

Schwannoma-like pleomorphic adenoma: A pathological quandary.

Pleomorphic adenoma usually presents as a painless growing mass in locations of the salivary glands and is notorious for local recurrence if previous surgical resection is incomplete. Schwannoma is a benign peripheral nerve tumor with microscopic features of sheets of spindle-shaped cells with nuclear palisading. However, when a pathologist encounters a salivary gland tumor with microscopic morphological features of biphasic components with areas of schwannoma-like morphology, it is crucial to make a prudent diagnosis by differentiating Schwannoma-like pleomorphic adenoma and its differential diagnosis as they have remarkably different outcome in patients. We herein present a case of Schwannoma-like pleomorphic adenoma and discuss its approach to diagnosis and literature search.

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

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. 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. 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. 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.

Atypical presentation of an ancient retroperitoneal schwannoma mimicking a renal hydatid cyst: a case report and literature review

Schwannomas are benign neurogenic encapsulated peripheral nerve tumors of Schwann cells that rarely occur in the retroperitoneum. We present a case of a 22-year-old man who presented with right flank pain and was initially diagnosed as hydatid cyst based on the imaging and borderline results of anti-echinococcus (IgG). Albendazole was prescribed and taken for 4 months with no response and later underwent surgical excision of the mass. The diagnosis and morphology confirmed the nature of the schwannoma. Complete surgical excision remains the gold standard for the management of these tumors. The preoperative diagnosis is usually difficult; however, the definitive diagnosis is made upon histopathological examination.Author name: Please confirm if the author name are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 4 Given name: Asad Shahzad, Last name: Hasan.correct

Ultrasound imaging of median nerve neurolipomatosis: literature review and clinical case description

Neurolipomatosis is a rare benign tumor of peripheral nerves. The nerves of the upper extremities are more often involved, in most cases, the median nerves in the carpal canal. Children and young people suffer mainly. The article describes a case of fibrolipomatous hamarthroma of the median nerve in a 24-year-old patient, the ultrasound image is compared with the results of intraoperative observation. Despite the characteristic clinical and pathomorphological picture of this condition, the issues of diagnosis and differential diagnosis remain relevant. A special role is given to ultrasound as a non-invasive, widespread method of lifetime diagnosis of the condition of peripheral nerves. The median nerve, due to its superficial location, is available for visualization, and understanding the ultrasound semiotics of fibrolipomatous hamartoma will allow timely determination of it at the stage of initial clinical manifestations and avoid unnecessary and aggravating neurological deficits of examination methods such as biopsy.

DDDR-03. DRUG REPURPOSING VIA ULTRA-HIGH THROUGHPUT 3D SPHEROIDS SCREENING FOR HUMAN SCHWANNOMA

Abstract Schwannoma is the most common benign peripheral nerve tumor occurring sporadically or as part of neurofibromatosis syndromes. While surgical resection can be used as the primary treatment option for Schwannoma, patients could face life-long repeated surgeries due to recurrence of syndromes that decreases the quality of life. Thus, non-invasive treatments for Schwannoma are highly demanded. To discover novel therapeutics for non-invasive Schwannoma treatment, in this project, we leveraged the benefits of drug repurposing high-throughput screening (HTS) of FDA-approved drugs using 3D spheroids derived from Schwannoma patient samples. Both 2D primary cells and 3D primary spheroids models were developed from an IRB-approved tumor bank of schwannoma patient samples. The 3D spheroids were validated to recapitulate the features of patient tumors. We then conducted an ultra-HTS(uHTS) in 1536-well format of 2036 FDA-approved drugs on the growth and viability of Schwannoma patient-derived 3D spheroids. Seven FDA-approved drugs were identified from the pilot screen to inhibit the growth of Schwannoma patient-derived 3D spheroids. These drugs offer potential to serve as pharmacotherapeutics for Schwannoma non-invasive treatment. Our results have demonstrated the capability of a drug repurposing strategy for Schwannoma using uHTS and a patient-derived tumor bank. We further demonstrated that patient-derived drug sensitivity signatures could be encoded from the screening data to enable clustering of patients, which accounts for heterogeneity in Schwannoma and avoids "one-size-fits-all" solutions in future non-invasive Schwannoma treatment studies.

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

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. 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. 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. 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.

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.

Benign peripheral nerve tumors: Analysis of 89 FNA cases emphasizing diagnostic accuracy and their morphologic spectrum.

Benign peripheral nerve tumors (BPNTs) are a heterogenous group of soft tissue tumors that include a variety of nerve sheath tumors, granular cell tumor (GCT), and ganglioneuroma. Only a few large studies exist on cytopathology and diagnostic accuracy using fine-needle aspiration (FNA) biopsy for this set of neoplasms. Both surgical and cytopathology files were searched for cases of BPNT. FNA biopsy was performed using standard techniques. Eighty-nine cases from 88 patients (male:female=1:1; age range: 16-85years, mean age,51years) met inclusion criteria. FNA sites included extremities (58, 65%), head/neck (14, 16%), deep (9, 10%), and trunk (8, 10%). Aspirates were from primary neoplasms in all but one instance. There were 65 schwannomas, seven neurofibromas, seven perineuriomas, seven GCTs, and three ganglioneuromas/neuromas. Aspirates of schwannoma, GCT, neurofibroma (NF), and perineurioma (PN) were correctly diagnosed in 86%, 100%, 29%, and 0% of cases, respectively. Five tumors (6%) were interpreted as either a specific sarcoma or suspicious for sarcoma. Remaining aspirates were classified as spindle cell neoplasm, salivary gland neoplasm, and nondiagnostic. Cytologic features for schwannoma, NF, PN, and ganglioneuroma showed spindle cell-dominant smears arranged mainly in syncytial clusters. GCT aspirates contained a population of epithelioid cells harboring coarsely granular cytoplasm and bare nuclei. Immunohistochemical (IHC) staining in 55 (62%) cases showed S-100 expression in 95%. FNA biopsy coupled with IHC is reliable in correctly classifying schwannoma and GCT, but less so for NF. Perineurioma can be mistaken for sarcoma.

Large schwannoma of the median nerve at the distal forearm

Introduction. Schwannoma, also known as neurilemmoma, is a rare but one of the most common tumors of the peripheral nerves. It originates from Schwann cells of the peripheral nerve sheaths. Schwannoma mostly occurs in adults between 20 to 70 years of age. The regions where the tumor most commonly occurs are the head and neck, but it can occur almost anywhere in the body or the organs. Schwannomas are usually up to 2.5 cm in size but may grow to 4?5 cm. In this study, the rare case of large schwannoma of the median nerve in the distal part of the forearm is presented. Case report. A 46-year-old male patient was referred to a plastic surgeon with a diagnosis of lipoma on the anterior side of the distal third of the left forearm. Ultra-sound and magnetic resonance imaging were done, and the surgery was performed after that. An encapsulated tumor of the median nerve was found, and the tumor was completely removed without nerve damage. Histological analysis showed a benign schwannoma of cellular type and biphasic shape. In the postoperative course, there was transient paresthesia. One year after surgery, no tumor recurrence nor neurological deficit was recorded. Conclusion. Schwannoma is the most common benign tumor of peripheral nerves. Schwannomas over 5 cm in size are extremely rare. Appropriate physical examination, pre-operative imaging studies, and histological verification are required for the final diagnosis. The method of choice in treating large schwannomas is complete surgical excision.

Ancient schwannoma (Neurilemmoma) of the tongue: A rare case report

Schwannoma or neurilemmoma is an uncommon, benign peripheral nerve tumor derived from Schwann cells. It is usually a slow growing, asymptomatic, well encapsulated tumor that arises in association with a nerve trunk.Here we present a rare case of Ancient Schwannoma in a 20 year old male. The patient presented with a small, slow growing asymptomatic mass on the dorsal surface of the tongue, present since past 1year. Lesion was completely excised. Diagnosis was confirmed by histopathology and immunohistochemistry.

Schwannoma of Common Peroneal Nerve in the Knee- A Case Report

Schwannomas are rare benign neurogenic tumors of peripheral nerves arising from neural sheath A 42-year-old male patient presented with the complaint of gradually increasing swelling in the posterolateral aspect of right knee for last 15-20 years. Initially it was painless but for last 10 years, it is painful especially after touching or pressing it and also on flexion and extension movements of the knee. For last 10-15 days, the pain is unbearable. His MRI revealed it to be Schwannoma of common Peroneal nerve. He was operated under spinal anesthesia .Enucleation of the tumor was done. Continuity of common peroneal nerve was ensured. After surgical intervention, the patient’s complaints completely disappeared in the post-operative period. Schwannoma of common peroneal nerve is a very rare tumor of knee and must be kept in differential diagnosis of tumor in the posterolateral aspect of knee joint and in cases of pain in knee.

Multiple ancient schwannomas of the ulnar nerve at distant sites: a case report

In rare cases, schwannoma—a benign peripheral nerve tumor—undergoes chronic degenerative changes and progresses to ancient schwannoma. Herein, we report the first case of ulnar nerve-derived multiple ancient schwannomas, which uncommonly developed in the extremities and major nerves. A 76-year-old female patient presented with tingling sensations in her left ring and small fingers. She had a gradually enlarging mass that had developed 40 years ago in the proximal upper arm and a new mass that had grown on the wrist for the past few years. Based on physical examination, ultrasonography, and magnetic resonance imaging, ancient schwannomas of the ulnar nerve were suspected. The older and larger mass in the upper arm was more entangled with nerve fascicles, having necrotic changes. Through meticulous dissection of the nerve fascicles, both masses were successfully enucleated, and pathological examination confirmed ancient schwannoma. As ancient schwannomas grow, they become more entangled with the nerves; thus, early surgical removal is recommended.

P.114 Benign tumors of peripheral nerves in children at a tertiary-care pediatric hospital

Background: Tumors affecting peripheral nerves in children are rare. Accurate diagnosis ensures that management is appropriate and timely. Methods: We review the clinical presentation and utility of investigations of children with intrinsic tumors affecting peripheral nerves at the Children’s Hospital of Eastern Ontario (CHEO). Results: From 2009-2019, 14 cases were identified. Mean age of symptom onset was 8.2 years (range 0.3 to 17.3 years). Presenting symptoms included painless muscle wasting (2/14), focal muscle weakness (7/14), contracture (1/14), pain (1/14) or a painless, palpable mass (3/14). MRI was useful at differentiating benign pediatric nerve tumors. Peripheral nerve lipomatosis demonstrated a classic “spaghetti string” appearance. Patients with perineurioma showed evidence of enhancing, nodular lesions while intraneural ganglionic cysts display cystic lesion within the nerve. Neurofibromas appear like a “bag of worms” while schwannomas are more eccentrically positioned around the nerve. Nerve conduction studies (NCS) or electromyography (EMG) were performed in 11/14 patients. Biopsies were performed in 9 patients and surgical management in 4 patients. Conclusions: The rare nature of peripheral nerve tumors in children can pose diagnostic challenges. NCS/EMG are important to assist with localization, and MRI important at distinguishing benign tumors. Key MRI, clinical and NCS features can guide management, potentially avoiding invasive procedures.