HRUS findings ranged from normal to widespread peripheral nerve involvement. Because the presence of plexiform neurofibromas and the benign tumor load are risk factors for the development of a malignant peripheral nerve sheath tumor, HRUS may be a useful tool to identify a subgroup of patients who could benefit from regular follow-up
. The vast majority are benign, however, malignant transformation is seen particularly in large tumors and those associated with neurofibromatosis type 1 (NF1) This case demonstrates classic findings of peripheral nerve sheath tumors on ultrasound as well as some characteristic signs on MRI. On the initial ultrasound evaluation, these masses embedded in the musculature of the calf were well circumscribed, heterogeneously hypoechoic, and displayed increased vascularity
On an Ultrasound, a Peripheral Nerve Sheath Tumors is usually well defined, round/ovoid, and hypoechoic with scattered low-level internal echoes A nerve sheath tumor may appear on imaging such as an MRI or ultrasound when a person is being evaluated for one of the symptoms listed above. Or the tumor can be an incidental finding — discovered when a doctor is using MRI to examine a person for something else, such as lower back pain Rhian Rhys, in Clinical Ultrasound (Third Edition), 2011. Nerve sheath tumours. Peripheral nerve tumours of the neck are rare. The most common are schwannomas and neurofibromas. Clinically, they are usually mistaken for a lymph node, but they have certain characteristic sonographic features which help in differentiating them from lymph nodes Nerve sheath tumors are neoplasms composed of cells showing nerve sheath differentiation .They represent 10-12 % of all soft tissue neoplasms .The fourth edition of the WHO Classification of Tumors of Soft Tissue and Bone, published in 2013, now incorporates a chapter specifically dedicated to nerve sheath tumors .Some of these tumors were previously classified under Tumors of the.
. Giant cell tumor of the tendon sheath 37. Epidermoid cyst (epidermal inclusion cyst) 38. Hemangiomas and vascular malformations 39. Peripheral nerve sheath tumours 40. Synovial sarcoma 41. Synovitis 42. Osteoarthritis 43. Bursitis 44. Cellulitis 45. Absces Purpose: To retrospectively evaluate the diagnostic accuracy of and complications from ultrasound-guided core needle biopsy (UGCNB) of suspected peripheral nerve sheath tumors (PNSTs). Methods: Patients undergoing UGCNB from January 2004 to December 2016, based on the suspicion of PNST, were included in the study. Age, gender, anatomical location, dates of relevant events, and. This was further confirmed intraoperatively, and pathologically was diagnosed as a malignant peripheral nerve sheath tumor (MPNST). In this present study the role of ultrasonography, the correlation between MRI and ultrasonographic findings are discussed and a review of the literature is presented
Peripheral nerve tumors also are readily identified by ultrasound 1. Vet Radiol Ultrasound. 1999 Jul-Aug;40(4):367-71. Magnetic resonance imaging and ultrasonography in the diagnosis of a malignant peripheral nerve sheath tumor in a dog. Platt SR(1), Graham J, Chrisman CL, Collins K, Chandra S, Sirninger J, Newell SM Benign peripheral nerve sheath tumors (PNSTs) represent approximately 10% to 12% of all benign soft-tissue neoplasms. 1 They are mostly characterized by neoplastic proliferations with Schwann cell differentiation. 2, 3 Schwann cells are a type of glial cell whose main role is to provide support to peripheral neurons and allow fast conduction of action potentials along axons by supplying myelin. Computed tomography (CT) with subsequent image-guided biopsy revealed an intraabdominal mass, which was identified as consistent with a malignant peripheral nerve sheath tumor (MPNST). At laparotomy, the mass measured 10 × 9 × 8 cm and encased the aorta and inferior vena cava. It was debulked, since full excision was not possible Distinctive features that suggest a peripheral nerve sheath tumor include a location in the region of a major nerve, depiction of the nerve entering or exiting the mass, and the presence of certain signs (split fat sign, fascicular sign, target sign). These features are summarized in the, Table
. One is said to have a peripheral nerve sheath tumor (PNST) if the cells constituting the layer, i.e. the peripheral nerve sheath, are growing at an abnormal rate High-resolution ultrasound (HRUS) is a well-established method for the examination of peripheral nerves. Several studies have demonstrated its high value for diagnosis and therapy planning in nerve trauma, polyneuropathies, mononeuritis, and nerve tumors [ 2, 7, 17, 30 ]
Ultrasound intrascrotal mass. Prognostic factors. Malignant transformation to malignant peripheral nerve sheath tumor in deeply seated neurofibromas in a subset of neurofibromatosis type 1 patients Nuclear atypia (focal or diffuse) are accepted in neurofibroma Malignant peripheral nerve sheath tumors usually have a guarded prognosis because in at least 72% of cases, the disease recurs after surgery. Since these lesions are not detected early, the limbs have to be amputated in most of the cases. The median survival time for dogs with malignant peripheral nerve sheath tumors is 2 years
The epithelioid subtype of malignant peripheral nerve sheath tumor is a rare entity and has not been studied as a separate entity. In our case, one of the features, peripheral enhancement was present (Figure 3). Yu et al. evaluated the radiological features of the malignant nerve sheath tumors and reported peritumoral edema, intratumoral. called peripheral nerve sheath tumors (PNSTs). These tumors usually grow along the nerve but do not typically spread to other sites in the body. Causes This type of cancer most commonly occurs in dogs; however , cats can also develop PNSTs. Affected animals are typically middle-aged to older. The cause of these tumors is unknown. Clinical Sign The most common benign peripheral nerve tumor in adults, a schwannoma can occur anywhere. It typically comes from a single bundle (fascicle) within the main nerve and displaces the rest of the nerve. Some schwannomas enlarge and assume unusual shapes within your spine or pelvis, such as dumbbell tumors The ultrasonograms of three patients with surgically proven benign tumors of the sciatic nerve sheath were reviewed. Two lesions were neurilemmomas and one was a neurofibroma. All lesions appeared. Emuaid© Gave Me My Life Back. I Am So Thankful For This Amazing Product.. User Reported 47% Average Reduction In Nerve Pain Within 6 Hours After Application
Conclusions: HRUS frequently showed subclinical involvement of the peripheral nerves in NF1, also when NCS were normal. HRUS findings ranged from normal to widespread peripheral nerve involvement. Because the presence of plexiform neurofibromas and the benign tumor load are risk factors for the development of a malignant peripheral nerve sheath tumor, HRUS may be a useful tool to identify a. An ultrasound-guided biopsy confirmed the diagnosis of the nerve sheath tumor as a benign schwannoma. Although the patient had 2 second-degree relatives with neurofibromatosis type 1, she did not meet diagnostic criteria for neurofibromatosis type 1. Surgical resection of the tumor was subsequently performed for symptomatic relief. Peripheral nerve sheath tumors can be seen in the following diagnostic imaging: Classic appearance on MRI scans; Visible on ultrasound or CT imaging; Biopsy of the affected area is rarely needed; Risk factors for peripheral nerve sheath tumors include a hereditary genetic link and for malignant peripheral nerve sheath tumors, previous exposure.
ultrasound were both negative for metastatic disease. Punch biopsies revealed the histopatho-logical diagnosis of a malignant peripheral nerve sheath tumor. Due to the extent of the primary mass, local excision was not possible, and amputation of the limb was not an option for the owner Ultrasound imaging revealed a 2-cm hypoechoic mass with well-defined margins in the left proximal lateral soleus, while Doppler ultrasound demonstrated increased color flow surrounding the mass. Magnetic resonance imaging findings were consistent with a nerve sheath tumor, and ultrasound-guided tissue biopsy determined the mass to be a benign. Nerve sheath tumors. Schwannoma in the hand at the base of the thumb. Bookmark . Clinical information Palpable mass in a patient known to have had multiple schwannomas. Ultrasound Images & Clips Schwannoma in the hand at the base of the thumb. Schwannoma in the hand at the base of the thumb. The same patient also had a schwannoma in the lower. 7.3.10 Peripheral nerve tumors; Malignant nerve tumors; Malignant nerve tumors. Malignant nerve sheath tumor. Bookmark . Ultrasound Images & Clips Malignant nerve sheath tumor. Malignant nerve tumors. and has worked in the Gelderse Vallei hospital from January 1, 1983. till July 1, 2014. He was the head of the ultrasound department for many. PNST Peripheral Nerve Sheath Tumor POEMS Polyneuropathy, Organomegaly, Endocrinopathy, M-protein, Skin changes TOS Thoracic Outlet Syndrome Peripheral Nerve Disorders (PND) Imaging Guidelines V1.1 _____ ©2020 eviCore healthcare
Pediatric and adult malignant peripheral nerve sheath tumors: an analysis of data from the surveillance, epidemiology, and end results program. J Neurooncol 2014; 116:609. Hagel C, Zils U, Peiper M, et al. Histopathology and clinical outcome of NF1-associated vs. sporadic malignant peripheral nerve sheath tumors. J Neurooncol 2007; 82:187 Peripheral nerve sheath tumors include benign lesions, or malignant tumors . In benign peripheral nerve sheath tumors, schwannomas and neurofibromas should be distinguished. Schwannomas (also called neurilemoma), arising from the Schwann cells of the neural sheath, are the most common peripheral nerve tumors and frequently emerge from the main. However, the accurate presurgical determination of rare and, in particular, malignant tumor entities such as malignant peripheral nerve sheath tumors (MPNSTs) remains insufficient even when advanced methods such as MRI (so-called MR neurography enhanced by, e.g., diffusion tensor imaging) or PET are used Malignant peripheral nerve sheath tumors used to be called neurofibrosarcomas. Malignant peripheral nerve sheath tumors can occur anywhere in the body, but most often occur in the deep tissue of the arms, legs and trunk. They tend to cause pain and weakness in the affected area and may also cause a growing lump or mass Our current research focuses on advanced imaging techniques such as Stimulated Raman Histology to develop improved intraoperative decision-making, attempting to understand the growth pattern of nerve sheath tumors (schwannomas and neurofibromas), and the evaluation of an approved device (Neurocap) for the treatment of nerve pain secondary to.
Although training in peripheral nerve surgery, whether during residency or fellowship, is recommended before operating on nerve sheath tumors (i.e., schwannomas and nonplexiform neurofibromas), the basic concept is straightforward: preserve the nerve (9, 14).Nevertheless, nerve sheath tumors, especially neurofibromas, continue to be removed en bloc with the parent nerve (5, 6) or not removed.  Nielsen GP, Antonescu CR, Lothe RA (2013) Malignant peripheral nerve sheath tumors. WHO Classification of Tumours of Soft Tissue and Bone. IARC 5: 187-189  Fletcher CDM, Bridge JA, Hogendoorn PCW, Mertens F (2013) WHO Classification of Tumours of Bone and Soft Tissue. Lyon The tumor cells showed positive reactivity for S-100 protein, NSE , GFAP , and p 75 but were negative for NF 200, NF 70, MAC 387, and melan A. The histomorphological features and immunohistochemistry results confirmed the diagnosis of malignant peripheral nerve sheath tumor (PNST) Orbital schwannoma is a rare type of peripheral nerve sheath tumor (PNST) that varies in clinical presentation. Orbital schwannomas typically involve the head and neck, and rarely occur within the orbit. Other tumor types within this family include neurofibromas and malignant PNSTs, which are more commonly seen in patients with. Background: Peripheral nerve sheath tumors (PNST) can be categorized into benign or malignant on the basis of imaging findings on ultrasonography (USG) and magnetic resonance imaging (MRI). Case Presentation: We report a case of a 28-year-old male presented with a huge swelling in his right forearm
Malignant peripheral nerve sheath tumor (MPNST) is a rare disease. The present study discusses the case of a 30-year-old male patient who presented with complaints of pain in the left testis and groin over 1 month. Ultrasonography and computed tomography (CT) imaging revealed the presence of a space-occupying lesion localized in the left testis Schwannoma is a rare and benign neoplasm which develops out of 'Schwann' cells or nerve sheath cells. Sometimes doctors also refer schwannomas as:-neurilemmoma; neurinoma; peripheral nerve sheath tumor; The concern with a breast schwannoma is that medics make a correct differential diagnosis because they can resemble a malignant neoplasm (breast cancer) mammographically
Giant cell tumors of the tendon sheath, or localized pigmented villonodular synovitis, has a characteristic appearance and location on Ultrasound. This lesion is most often associated with the flexor tendon sheath of the finger and is at least partially in close contact with a tendon sheath; however, the lesion characteristically does not move. Ultrasound. A scan that uses sound waves to create images from within the body. CT. The Computer Tomography (CT) scan takes a number of x-rays to make a 3D image of an affected area. EUS. The Endoscopic Ultrasound Scan (EUS) uses a tube-like instrument called an endoscope with an ultrasound scanner attached Peripheral Nerve Sheath Tumors. My husband was diagnosed in March 2008 with high grade, stage 3, aggressive, Malignant Peripheral Nerve Sheath Tumor/soft tissue sarcoma a month AFTER the grapefruit sized tumor was surgically removed from his sciatic nerve in his pelvis. My husband is now undergoing chemotherapy with plans to have radiation too Sonographic characteristics of peripheral nerve sheath tumors. AJR Am J Roentgenol 2004;182:741-744. 14. Kolberg M, Holand M, Agesen TH, Brekke HR, Liestol K, Hall KS, et al. Survival meta-analyses for >1800 malignant peripheral nerve sheath tumor patients with and without neurofibromatosis type 1. Neuro Oncol 2013;15:135-147. 15 The doppler function highlighted vasculature structures, differentiating vascular from relevant nerve anatomy or tumor structures (Figure 1). Despite well-described sonographic details of peripheral nerve sheath tumors, the efficacy and outcomes of regional blockade in patients with NF1 is limited
The neurofibromatoses (NF) type 1 and 2 are hereditary tumor predisposition syndromes caused by germline mutations in the NF1 and NF2 tumor suppressor genes. In NF1 and 2, peripheral nerve tumors occur regularly. For further characterizing nerve ultrasound was performed in patients with NF1 and 2 Rationale: Malignant peripheral nerve sheath tumor occurring in the context of neurofibromatosis type I (NF1) is relatively rare. Herein, we report a case of NF1 with malignant peripheral nerve sheath tumor in the upper arm.. Patient concerns: A 24-year-old man presented with a mass in the medial part of the left upper arm that had been present for more than 20 years We report a novel case of endoscopic ethanol ablation of a peripheral nerve sheath tumor presenting as a small bowel obstruction. Introduction Ethanol is a widely available and cost-effective agent, which, when used for ablation, induces rapid cell death by means of cell lysis, protein denaturation, and vascular occlusion Peripheral nerve sheath tumours (PNSTs) are neoplasms originating from Schwann cells, perineural cells and intraneural fibroblasts. Sub-classifications are used in human medicine (eg, Schwannoma, neurofibroma); however, owing to unclear histiogenesis, in veterinary medicine they are usually divided into benign or malignant (MPNST). 1 -3 Feline PNSTs are uncommonly reported, usually occur in.
Peripheral nerve tumors are rare in the cat. Various names used, but accepted nomenclature is either benign or malignant peripheral nerve sheath tumor (PNST). Benign PNST (1.8% of feline skin and subcutaneous neoplasms) occur more often on head and neck. Malignant PNST occur more often on head and forelimb Other times, a growth may arise from the nerve itself. We treat all tumor types located in peripheral nerves, such as schwannomas, neurofibromas, malignant peripheral nerve sheath tumors, and perineuriomas, or in the networks of nerves serving the arms and legs: the brachial plexus and lumbar plexus
Malignant peripheral nerve sheath tumor (MPNST) is a rare disease. The present study discusses the case of a 30‑year‑old male patient who presented with complaints of pain in the left testis and groin over 1 month. Ultrasonography diagnosis of the tumor. Brightness‑mode ultrasound examina‑. Participants are expected to understand the principle imaging characteristic of the peripheral nerve sheath tumour and to create a correlation between imaging findings and histologic types. Topics Peripheral nerve sheath tumor Neuromuscular ultrasound is a beautiful example of multi- and interdisciplinary work. Various professionals apply ultrasound for different indications and will experience neuromuscular ultrasound as a natural extension of their expertise, because they are already in contact with peripheral nerve disorders. Among the groups of potential. Adjuvant radiotherapy can be given to reduce the tumor load. Chemotherapy can be given with ifosumide and doxorubicin. Malignant pancreatic nerve sheath tumours are very rare to be found, but have very poor prognosis, hence in cases of pancreatic tumour its better to keep the diagnosis of nerve sheath tumour also a differential diagnosis
Of note, though Schwannomas are the more common benign peripheral nerve tumor, Neurofibromas are more likely to precipitate symptoms (pain, neuropathic symptoms like pins and needles, etc). Mainstay of management is usually surveillance if asymptomatic, given their low-risk profile Other Nerve Sheath Tumors Malignant Peripheral Nerve Sheath Tumor (MPNST) Malignant. Adults. Frequently in setting of NF1. Often poor prognosis. Must arise from a peripheral nerve or pre-existing IHC: deep soft tissue. ) Schwannomas are a benign peripheral tumor that form from the Schwann cells. Schwann cells are cells in the peripheral nervous system that produce the protective lining (sheath) of a nerve. Schwannomas are caused by a DNA mutation which causes Schwann cells to rapidly multiply Peripheral nerve sheath tumors are either benign or malignant. Initially for malignant peripheral nerve sheath tumor (MPNST), various terminologies such as malignant schwannoma, malignant neurilemmoma, neurofibrosarcoma, and neurogenic sarcoma were used. To avoid confusion, World Health Organization coined the term MPNST
Imaging showed an enhancing, cystic mass in the right upper pelvis continuous with the S1 nerve root suspicious for nerve sheath tumor. The mass was resected and a diagnosis of SFT was made. Conclusions: While the patient's mass was initially thought to be a peripheral nerve sheath tumor, pathology revealed that it was a SFT. We highlight the. Malignant peripheral nerve sheath tumor (MPNST) is a rare disease. The present study discusses the case of a 30‑year‑old male patient who presented with complaints of pain in the left testis and groin over 1 month. Ultrasonography and computed tomography (CT) imaging revealed the presence of a space‑occupying lesion localized in the left testis Diagnosis generally reserved for any spindle cell sarcoma arising from a nerve or neurofibroma, or showing nerve sheath differentiation. At least half of MPNST's occur in patients with neurofibromatosis (although only 4-5% of NF-1 patients experience malignant transformation of their tumors) As an example, ultrasound may be used to identify the location of normal nerve fascicles in relation to peripheral nerve sheath tumors, thus minimizing the chance of iatrogenic nerve injury. 20 The addition of MB staining of the chosen surgical path may further improve the safety and efficiency of the surgical procedure
Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma. This tumor included up to 10% of 1-2 of 100,000 population/year soft tissue sarcoma. This paper presents a MPNST case at superficial body, such as frontal, temporal and parietal head, neck, trunk, left arm, and visceral organs likes brain, lung, liver, right kidney, lef Glandular Peripheral Nerve Sheath Tumors James M. Woodruff, M.D., and Wayne N. Christensen, M.D. Background. Peripheral nerve tumors (PNT) con- taining glands are uncommon. Which types of PNT con- tain glands is a matter of controversy, a factor bearing on the prognosis of these tumors. Methods. The authors reviewed the files of 11 pa Malignant Peripheral Nerve Sheath Tumors (MPNSTs) of the prostate are extremely rare. A very unusual case of simultaneous adenocarcinoma and MPNST of the prostate is reported. A 60-year-old Caucasian male presented for annual urologic examination. Digital rectal examination revealed a painless, toughish, and asymmetrically enlarged prostate Sarcomas are a rare type of breast malignancies and malignant peripheral nerve sheath tumors of the breast are even rarer. There are no specific clinical and radiological features for the diagnosis of this tumor and histological features are also reported to be nonspecific. Therefore, immunohistochemistry is required for its diagnosis. A definitive treatment protocol is unavailable because of.
Malignant peripheral nerve sheath tumour (MPNST) is the sixth most common type of soft-tissue sarcoma, accounting for approximately 5 to 10% of cases [1,2,3].Although its exact cellular origins remain unclear, most MPNSTs arise in association with a peripheral nerve and are hypothesized to be of neural crest origin [3, 4].Gastrointestinal malignant peripheral nerve sheath tumours are rare, and. peripheral nerve sheath tumor: a case report and review of the literature Md Shuayb1* and Rabeya Begum2 Abstract Background: Sarcomas are a rare type of breast malignancies and malignant peripheral nerve sheath tumors of the breast are even rarer. There are no specific clinical and radiological features for the diagnosis of this tumor Developed by renowned radiologists in each specialty, STATdx provides comprehensive decision support you can rely on - Nerve Sheath Tumors. link. Bookmarks (0) Ultrasound. Diagnosis. Musculoskeletal. Neurovascular Abnormalities. Nerve Sheath Tumors ;. A very small percentage of nerve sheath tumors are malignant. These are known as malignant peripheral nerve sheath tumors, or neurofibrosarcomas. Because neurofibrosarcoma originates in nerves, it. 10% of benign soft tissue neoplasms Derived from Schwann cells Most common types - Schwannomas (neurilemmomas) and neurofibromas Others include Traumatic neuroma (stump neuroma), Mortans neuroma, Neural fibrolipoma, Nerve sheath ganglion, Intraneural perineuroma, Malignant peripheral nerve sheath tumors(7-8%) Difficult to distinguish them with imagin
The signs and symptoms of Benign Peripheral Nerve Sheath Tumors of Breast may include: A benign lump in a single breast; typically, only one breast is affected. The tumors can appear as firm, painless nodules. Larger tumors may be felt by touch; small tumors may be missed during a mammogram screening Background: The most common location of malignant tumors of the peripheral nerve sheath in the spinal cord is the intradural-extramedullary region, and is rare in the spinal nerve roots in the lumbar region.They mainly affect large female dogs over six years of age. Imaging tests assist in the presumptive diagnosis, but confirmation requires histopathological and immunohistochemical examination A peripheral nerve tumor is a growth which starts on or within the nerve itself. Often, these tumors are benign. The tumor is generally a slow growing mass along the path of the nerve. These tumors arise from the nerve itself, most commonly from their sheet (schwannoma), and less frequently from fibrous tissue within the nerve (neurofibroma) A Miller School study led by Allan D. Levi, M.D., Ph.D., highlighting patient safety concerns with biopsies of benign peripheral nerve sheath tumors has been recognized as the Paper of the Year by the Congress of Neurological Surgeons (CNS) - the second year in a row that Dr. Levi has received this distinction Ultrasound demonstrated the responsible pathology (in 43 of 46 patients; sensitivity, 93%) more frequently than MRI did (in 31 of 46 patients; sensitivity, 67%). The two techniques were equally specific (86%) in excluding focal nerve pathology. The superior accuracy of ultrasound for the diagnosis of focal peripheral nerve pathology, combined.
Benign peripheral nerve sheath tumors are divided into 2 major groups: schwannomas (neurilemomas) and neurofibromas (3). Schwannomas can be easily shelled out while preserving nerve contiguity. In most neurofibromas, the nerve is incorporated within the mass, and the required surgery includes resection and subsequent nerve grafting to preserve. Malignant peripheral nerve sheath tumors (MPNSTs) account for approximately 10% of all soft tissue sarcomas. They are commonly associated with neurofibromatosis type 1 (NF-1) (50%), but also occur postradiation (10%) or sporadically (40%). Most MPNSTs are aggressive with high rates of recurrence (40%) and distant metastases (60%) N2 - Background Tenosynovial giant cell tumors are a group of slowly growing benign neoplasms of synovial membrane of joints, tendons, and bursae. The localized type or giant cell tumor of tendon sheath (GCTTS) is the extra-articular form of tenosynovial giant cell tumors. We describe two patients with a GCTTS, confirmed histologically at the. Arshi A et al: Malignant peripheral nerve sheath tumors of the head and neck: Demographics, clinicopathologic features, management, and treatment outcomes. Oral Oncol. 51 (12):1088-94, 2015. Soldatos T et al: Advanced MR imaging of peripheral nerve sheath tumors including diffusion imaging Ultrasonography is helpful to differentiate between solid and cystic masses and surgical resection has to preserve nerve fascicles where it's possible mainly when a motor branch is involved. References. Cimino-Mathews AM (2011)Peripheral nerve sheath tumors. Surgical Pathology 4: 761-782
The lesion was highly suspicious for a peripheral nerve sheath tumor. At necropsy, the eagle weighed 5.26 kg and was in a good body condition. Internal organs appeared normal, except the liver and kidneys, which were slightly swollen. On the left side, at the root of the spinal nerve between C6 and C7, an approximately 3 × 5 mm large mass was. Mucosal nerve sheath tumors have been well described in the gastrointestinal tract and other mucosal sites. In a series of mucosal biopsies, we have encountered a distinct subset of mucosal peripheral nerve sheath tumors characterized by small epithelioid cells and a benign clinical course Nerve Sheath Tumor in Dogs. Nerve sheath tumors are tumors that grow from the myelin sheath that covers the peripheral and spinal nerves. This type of tumor affects the nervous system of the body, as it compromises the functioning ability of the peripheral and/or spinal nerves that form the peripheral nervous system and which reside or extend outside the central nervous system (CNS) Peripheral nerve sheath tumors (PNSTs) may arise sporadically or in the presence of genetic disorders, including neurofibromatosis (NF) types 1 and 2, schwannomatosis, and in patients with large genetic deletions involving the CDKN2A gene. Surgical resection is the treatment of choice for symptomatic PNSTs and offers patients a potential cure; however, pre-existing conditions or tumor location. Typically, peripheral nerve sheath tumors are categorized as either schwannoma or neurofibroma, both of which are associated with neurofibromatosis. Both cat-egories of nerve sheath tumors have similar imaging find-ings; however, they can be differentiated by their configuration relative to the affected nerve (Fig. 6). On CT imaging, they tend.