Rapidly Growing Leiomyoma Mimicking Schwannoma of the Saphenous Nerve in the Lower Extremity: An Unusual Case Report.

Leiomyomas and schwannomas are both types of rare benign soft tissue tumours. Leiomyomas are more commonly found in the lower limbs than in the upper extremities, while schwannomas are rare peripheral nerve sheath tumours that can occur in different anatomical regions. However, they rarely occur in the saphenous nerve. This case study presents a 41-year-old female patient with a solitary mass lesion located deep in the soft tissue of the anteromedial lower extremity. The physical examination revealed a palpable, elastic-hard, mobile and non-tender mass. Magnetic resonance imaging (MRI) showed an oval-shaped subcutaneous mass on contrast-enhanced T1-weighted sections. The initial MRI images suggested a schwannoma, but the tumour was later confirmed to be a leiomyoma after total enucleation. An immunohistochemical study was performed for differential diagnosis. Solitary mass lesions in the lower extremities can be mistaken for various types of tumours and misdiagnosed and require histopathological examination and good radiological imaging for differential diagnosis. Complete surgical excision is usually a safe and effective treatment for leiomyomas.

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.

Myxofibrosarcoma involving the sciatic nerve: From ultrasonography to histopathology.

Myxofibrosarcoma (MFS) is a unique soft tissue (fibroblastic) sarcoma, characterized by malignant with a locally infiltrative behavior. In this case image, we aimed to report an uncommon/challenging scenario of MFS involving the scatic nerve in which the potential contribution of ultrasound examination has been touched upon.

[Schwannoma of Intercostal Nerve Resulting in Significant Pain Relief Following Excision:Report of a Case].

An 80-year-old male underwent chest computed tomography (CT) due to complaints of right-sided chest pain. A chest wall tumor was identified in the right eighth intercostal space, corresponding to the location of his pain. The patient was subsequently referred to our department for further evaluation and treatment. Utilizing single-port thoracoscopic surgery, the tumor was successfully excised. Intraoperatively, the tumor was found beneath the parietal pleura, was contiguous with to the intercostal nerve. Histopathological analysis confirmed the diagnosis of schwannoma originating from the intercostal nerve. The right-sided chest pain was reduced after operation significantly. No recurrence or relapse of symptoms was observed during follow-up. Although schwannoma of the chest wall in asymptomatic in many cases, in this case, localized pain corresponding to the tumor site was evident. This emphasizes the importance of considering schwannoma in the differential diagnosis of chest pain.

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.

Ultrasound and MR imaging of peripheral nerve tumors: the state of the art.

Peripheral nerve sheath tumors are a heterogeneous subgroup of soft tissue tumors that either arise from a peripheral nerve or show nerve sheath differentiation. On imaging, direct continuity with a neural structure or location along a typical nerve distribution represents the most important signs to suggest the diagnosis. Ultrasound and magnetic resonance imaging are the best modalities to evaluate these lesions. First, it is necessary to differentiate between a true tumor and a non-neoplastic nerve condition such as a neuroma, peripheral nerve ganglion, intraneural venous malformation, lipomatosis of nerve, or nerve focal hypertrophy. Then, with a combination of clinical features, conventional and advanced imaging appearances, it is usually possible to characterize neurogenic tumors confidently. This article reviews the features of benign and malignant peripheral nerve sheath tumors, including the rare and recently described tumor types. Furthermore, other malignant neoplasms of peripheral nerves as well as non-neoplastic conditions than can mimick neurogenic tumor are herein discussed.

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.

Plexal intraneural perineurioma: an analysis of the clinicoradiologic presentation of this rare variant.

PURPOSE: Intraneural (IN) perineurioma is a rare benign peripheral nerve sheath tumor, typically presenting as a painless, progressive mononeuropathy in adolescents. A rare plexal variant has been described, although there are little data describing its clinicoradiologic features. Herein, we present the largest case series of plexal IN perineuriomas reported in the literature. METHODS: Electronic medical records (EMR) from 1990 to 2022 from a single academic institution were reviewed for a diagnosis of IN perineurioma involving the brachial or lumbosacral plexus. This identified 18 patients, of which 17 had available MR imaging. We reviewed the EMR for demographics, clinical presentation, imaging characteristics, and surgical outcomes. RESULTS: Eighteen patients were identified. Most patients were male (11/18, 61%) and first developed symptoms at the age of 9.6 years (range 7 months to 55 years). Diagnosis occurred on average at the age of 22 years (4-57 years), which is significantly earlier than distal IN perineurioma (p = 0.0096). All patients (100%, 17/17) presented with motor polyneuropathy and muscular atrophy in multiple nerve distributions, with associated sensory loss (12/17, 71%). Most plexal lesions occurred in the brachial plexus (66%, 12/18). Five (29%, 5/17) patients presented with a hand/foot discrepancy, and 5 patients (29%) had a limb length discrepancy. Five patients underwent tendon transfer, of which two had failure of tendon transfer at most recent follow-up (50%, 2/4) due to progression of neurologic loss affecting the donors. Of patients managed nonoperatively, 87% of patients (6/7) with follow-up information demonstrated disease progression with worsening motor function or sensory loss, and 2 patients demonstrated progression on imaging at most recent follow-up. CONCLUSIONS: Plexal perineurioma represents an uncommon variant of IN perineurioma that presents as a progressive motor and sensory polyneuropathy in childhood or early adolescence. Surgical management remains controversial, and tendon transfer tends to result in poor long-term surgical outcomes.

Magnetic Resonance Imaging of Nerve Tumors.

Nerve tumors are uncommon soft tissue neoplasms predominantly arising from peripheral nerve sheath and Schwann cells. We review the manifestations of benign peripheral nerve sheath tumors, concentrating on distinguishing imaging features of schwannomas versus neurofibromas with an emphasis on treatment implications. Nevertheless, there is often an overlap between the imaging presentation of these two conditions, making the accurate radiologic diagnosis challenging. Therefore, tissue sampling is often needed for a definitive histologic diagnosis. Treatment planning largely depends on symptoms, location of the lesion, and underlying risk factors. Three major syndromes, neurofibromatosis type 1, type 2, and schwannomatosis, predispose patients to peripheral nerve sheath tumors (PNSTs), with particular concern about the malignant subtype expression. In patients with suspected PNSTs, correlation of imaging findings with clinical findings and genetic tests is helpful for a more accurate diagnosis and disease management. Some imaging features on magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography can be helpful to differentiate malignant from benign subtypes.

Presurgical Perspective and Postsurgical Evaluation of Morton's Neuroma and Other Nerve Lesions.

Magnetic resonance imaging (MRI) is a robust method used for both preoperative and postoperative evaluation of Morton's neuroma and other neural lesions. MRI is used to confirm the diagnosis and for precise localization, estimation of outcome, and differential diagnoses. The differential diagnoses include mechanically induced plantar plate ruptures with associated Morton's neuroma-like tumors in the intermetatarsal/interdigital spaces; mechanical fibrosis cushion formations and pseudo bursae in the plantar foot adipose tissue; rheumatologic affections, such as rheumatoid nodules, gouty nodules, and intermetatarsal bursitis; and lastly the tenosynovial giant cell tumor (formerly called pigmented villonodular synovitis). In the postoperative evaluation after resection of Morton's neuroma, the same differential diagnoses must be considered as in the preoperative evaluation. Similarly, a high prevalence (up to 25%) of asymptomatic Morton's neuroma-like findings in the intermetatarsal and interdigital spaces should be kept in mind when interpreting postoperative recurrent forefoot pain after Morton's neuroma resection.

Saphenous nerve schwannoma as a cause of vascular claudication - case report and review of the literature.

Schwannomas are peripheral nerve tumours that are uncommon. They typical present with a palpable mass, pain or neurological changes. We describe a saphenous nerve schwannoma compressing the superficial femoral artery and causing vascular claudication. We also review the literature.

Diagnosis of cervical plexus tumours by high-frequency ultrasonography.

BACKGROUND: Cervical plexus (CP) tumours are difficult to diagnose because of atypical symptoms. This study aimed to summarize the features of a normal CP and CP tumours observed on high-frequency ultrasonography. METHODS: The ultrasound data of 11 CP tumour patients and 22 normal volunteers were collected. All 11 patients underwent magnetic resonance imaging (MRI), and 4 patients also underwent computed tomography (CT). The imaging data were compared with surgery and pathology data. RESULTS: The C7 vertebra and bifurcation of the carotid common artery (CCA) were useful anatomic markers for identifying the CP. In contrast to the C1 nerve (22.7%), the C2-4 nerves were well displayed and thinner than the brachial plexus (P < 0.05). CP tumours were more common in females (72.7%) and generally located at C4 (72.7%) on the right side (81.8%). Additionally, the nerve trunk in tumour patients was obviously wider than that in normal controls (7.49 ± 1.03 mm vs 2.67 ± 0.36 mm, P < 0.01). Compared with pathology, the diagnostic rates of CP tumours by MRI, CT and high-frequency ultrasound were 72.7% (8/11), 25% (1/4) and 90.9% (10/11), respectively. CONCLUSIONS: The diagnosis of CP neuropathy is accurate and reliable by high-frequency ultrasound, and the C7 vertebra and bifurcation of the CCA are useful anatomic markers in CP ultrasonography.

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.

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 (ADCmin), and standard uptake values (SUVmax) 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 ADCmin (0.5-0.7 × 10-3 mm2/s), and variable metabolic activity (SUVmax 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.

New method for the assessment of perineural invasion from perihilar cholangiocarcinoma.

PURPOSE: Perineural invasion (PN) is often found in perihilar cholangiocarcinoma. New procedure was developed to assess PN around the right hepatic artery (RHA) using dual-energy computed tomography (DECT). METHODS: Thirty patients with perihilar cholangiocarcinoma who underwent DECT before biliary drainage were retrospectively reviewed. Mask images, i.e., the periarterial layer (PAL) around the RHA and superior mesenteric artery (SMA), were made from late arterial phase DECT. The mean CT number of the PAL was measured. RESULTS: Twenty patients with PN around the RHA were classified into the PN (+) group. The remaining 10 patients without PN and other 26 patients with other diseases that are never accompanied with PN were classified into the PN (-) group. The PAL ratio (the CT number of the PAL around the RHA relative to that around the SMA) was calculated. Both the mean CT number of the PAL around the RHA and the PAL ratio were significantly higher in the PN (+) group than in the PN (-) group. According to an ROC analysis, the predictive ability of the PAL ratio was superior. Using the cutoff value of the PAL ratio 1.009, a diagnosis of PN around the RHA was made with approximately 75% accuracy. CONCLUSIONS: Assessment with CT number of the PAL reconstructed from DECT images is an easy and objective method to diagnose PN.

[Synchronous schwannoma and ependymoma of the cauda equina]. / Sochetanie shvannomy i ependimomy konskogo khvosta spinnogo mozga.

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.

Cervical Vagal Schwannoma Causing Asymptomatic Internal Carotid Artery Compression.

BACKGROUND: Schwannoma originating from the cervical vagus nerve is a rare neoplasm. Vagal nerve schwannoma (VNS) usually occurs between the third and fifth decades of life. METHODS: We operated one patient for cervical schwannoma causing internal carotid artery (ICA) compression. RESULTS: The patient underwent en bloc excision via transcervical approach under general anesthesia. Pathological examination demonstrated the diagnosis of schwannoma. CONCLUSIONS: Our case shows that VNS can cause ICA compression and therefore brain ischemia.

Role of high-resolution ultrasound in detection and monitoring of peripheral nerve tumor burden in neurofibromatosis in children.

PURPOSE: Peripheral nerve sheath tumors are hallmark findings in neurofibromatosis types 1 and 2. With increasing size, they typically lead to neurological symptoms, and NF1 patients have a lifetime risk of 8-13% for developing malignant peripheral nerve sheath tumors. Medical imaging is therefore highly needed for early detection and exact localization of symptomatic or potentially malignant tumors. This review will give an overview of the ultrasound characteristics of peripheral nerve sheath tumors and findings in patients with neurofibromatosis types 1 and 2. METHODS: A systematic search of electronic databases, reference lists, and unpublished literature was conducted including the keywords "schwannoma," "neurofibroma," "neurofibromatosis," "benign and malignant peripheral nerve sheath tumor." RESULTS: The high-resolution allows a clear analysis of tumor echotexture, definition of margins, and the relation to the parent nerve. The use of color duplex/Doppler and contrast agent adds valuable information for the differentiation of benign and malignant tumors. CONCLUSION: High-resolution ultrasound is a well-established, non-invasive, and easily repeatable first-line tool in diagnostic procedures of soft tissue tumors.

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.