周围神经鞘瘤的CT和MRI分析

目的:分析周围神经鞘瘤的CT和MRI征象及病理组织学表现.方法:回顾性分析我院经手术病理证实的周围神经鞘瘤30例的CT和MRI征象及病理表现.结果:病变发生在颈部10例、胸部6例、腹部7例(含胃部4例)、四肢7例.30例周围神经鞘瘤中25例为良性,5例为恶性.20例行CT检查,其中17例良性病灶平扫密度较均匀,4例可见点状钙化灶,增强扫描病灶呈轻至中度强化,3例恶性病灶瘤体巨大,囊变、坏死多发,增强扫描强化不均匀.10例周围神经鞘瘤行MRI检查,MRI表现:T1WI病灶呈等或稍低信号,T2 WI呈高信号,增强扫描不均匀强化,10例病灶中,2例为恶性周围神经鞘瘤并伴淋巴结转移.结论:周围神经鞘瘤的CT和MR1表现具有特征性,CT和MRI能准确地显示肿瘤形态、部位、内部结构及与邻近结构的关系,对诊断有重要帮助,对手术治疗具有重要指导作用.     

周围神经鞘瘤115例影像诊断

神经鞘瘤,又称神经鞘膜瘤,由神经外胚层演化而来,起源于神经鞘膜雪旺细胞。以30～50岁多见。该瘤生长缓慢,多单发,无明显症状,多为偶然发现,部位分布广,好发于中枢神经系统及较大的周围神经干、脊柱旁区。笔者回顾性分析经CT、MRI检查并手术病理证实的115例周围神经鞘瘤,探讨周围神经鞘瘤的影像学表现,以充分了解此病变并与其他疾病鉴别,提高术前诊断水平。     

超声鉴别诊断体表孤立性神经鞘瘤及神经纤维瘤的价值

目的探讨超声对体表孤立性神经鞘瘤及神经纤维瘤进行鉴别诊断的价值。方法回顾性分析116例经病理证实的体表孤立性良性神经源性肿瘤患者的超声表现,重点观察肿物与周围神经的关系。结果超声对神经鞘瘤、神经纤维瘤的诊断符合率分别为70．9％,65．1％,对神经源性肿瘤的诊断符合率为84．5％。神经鞘瘤及神经纤维瘤在形态、大小、边界、内部回声、血流信号等方面的声像表现非常相似。周围神经在神经鞘瘤包膜外“绕过”,而在神经纤维瘤中央“穿过”。结论超声可根据体表孤立性神经鞘瘤及神经纤维瘤与周围神经关系对其进行鉴别诊断。     

周围神经鞘肿瘤的MR表现

周围神经鞘肿瘤不常见,两种主要的良性肿瘤为神经纤维瘤和神经鞘瘤(雪旺氏瘤),恶性肿瘤最常称为恶性周围神经鞘瘤(恶性雪旺氏瘤)。作者报告了22个(17例患者)经组织学证实的此类肿瘤的MR表现。其中雪旺氏瘤12个,神经纤维瘤7个,恶性周围神经鞘瘤3个(2个发生于神经纤维瘤病患者)。平均年龄36岁(14～75岁),女9例,男8例。64%发生于下肢,32%发生于上肢,仅4%发生于前腹壁,最常受累的下肢部位为大腿,大多数肿瘤位于发病肢体的前间隔,5例位于皮下,仅3例位于后间隔,1例丛状神经纤维瘤侵犯多个间隔。在MR图象上,肿瘤的大小为1～24cm,雪旺氏瘤3.6cm,神经纤维瘤3.9cm,恶性者10.6cm,11个肿瘤为卵圆形,10个为梭形,1个丛状     

本期读片窗答案

手术所见 :肿块位于左肾周脂肪囊内 ,质硬 ,与肾前缘相连 ,行肿块及左肾切除。肿块切面见坏死灶 ,周边部为脂肪组织。术前诊断 :腹膜后错构瘤或畸胎瘤。术后病理诊断 :腹膜后恶性神经鞘瘤累及左肾。讨论 :神经鞘瘤是来自周围神经鞘膜雪旺氏细胞的肿瘤 ,可发生于全身任何具有雪旺氏细胞的周围神经。有良性及恶性之分 ,恶性少见。本例恶性神经鞘瘤发生部位特殊 ,容易导致误诊。该肿瘤密度不均匀 ,呈不均匀强化 ,边缘不规则及与肾脏前缘分界不清应考虑为恶性 ;肿块周围低密度脂肪组织并非来自肿瘤本身 ,而是肾周囊状脂肪层受到肿瘤不同程度的侵…     

后纵隔少见神经源性肿瘤的临床和影像学表现

神经源性肿瘤是常见的纵隔肿瘤 ,几乎 90 %发生于后纵隔[1] 。神经鞘瘤及神经纤维瘤是常见的后纵隔神经源性肿瘤。后纵隔少见神经源性肿瘤按其起源可分为 :(1)起源于神经鞘的外周神经性的恶性神经鞘瘤、恶性神经纤维瘤 ;(2 )起源于交感神经肿瘤的神经节细胞瘤、神经节神经母细胞瘤、神经母细胞瘤 ;(3)起源于副交感神经的副神经节瘤[2 ] 。为了提高影像学对这些少见肿瘤的诊断认识 ,现综述如下。1　恶性神经鞘瘤及恶性神经纤维瘤 (malignantschwan nomaandmalignantneurofibromatosis)恶性神经鞘瘤和恶性神经纤维瘤共同起源于神经鞘膜 ,为少…     

乳腺原发性恶性周围神经鞘膜瘤一例

本文报道乳腺原发性恶性周围神经鞘膜瘤1例。患者女,18岁。主要临床表现为右侧乳房肿块,呈无痛进行性增大。超声表现为右侧乳房混合性巨大囊实性包块,边界尚清,可见少许血流;MRI表现为右侧乳房一巨大肿块,反转恢复序列脂肪抑制T2WI呈不均匀高信号,内见低信号分隔影,T1WI呈等低信号,边界清晰,DWI上肿瘤信号不均,以高信号为主,动态增强扫描示瘤体边缘及实性成分呈斑片状、结节状不均匀明显强化。病理诊断:右侧乳腺恶性周围神经鞘膜瘤。     

恶性周围神经鞘膜瘤的临床研究(36例报告)

为探讨恶性周围神经鞘膜瘤 (MNST)的临床及肿瘤生物学特征。对 36例MNST患者的临床病理资料及随访资料进行统计分析 ,并与国外文献结果作对照。结果显示 ,MNST以 4 0～ 6 0岁年龄组患病比例最高 ,男∶女为 2 6∶1,发病部位依次为躯干 >四肢 >头颈部 ;术后复发率为 4 2 10 % ,5年存活率为 8 33% ;未发现由神经鞘瘤或神经纤维瘤病恶变所致病例 ,也未发现与放疗后恶变有关的病例。提示MNST是一种原发的软组织恶性肿瘤 ,早期手术彻底切除是治疗的关键 ,其肿瘤生物学特征与国外资料报道有所差异     

胃恶性神经鞘瘤一例报告

神经鞘瘤是周围神经末稍的神经鞘源性肿瘤,可以发生在身体任何部位的末稍神经,而发生在胃者较为罕见。病理学上,以往与神经纤维瘤相混,现在已明确分开,命名为神经鞘瘤(Neurilemmoma,或Schwannoma)。我们遇到一例胃恶性神经鞘瘤,在X线表现上酷似平滑肌瘤,手术前曾诊断为平滑肌肉瘤,现报告如下。     

恶性钙化性周围神经鞘瘤一例

恶性钙化性周围神经鞘瘤一例田乃正患者女，１５岁。左大腿下端无痛性包块，４年来多次复发和切除，曾诊断为神经鞘瘤。半年前在原患部再次出现包块，短期内增长迅速，疼痛，遂来院诊治。检查：左大腿窝部后外侧软组织梭形肿胀，并扪及一４ｃｍ×８ｃｍ大小肿块，质硬，边...     

Peripheral tumor and tumor-like neurogenic lesions

Neoplasms of neurogenic origin account for about 12% of all benign and 8% of all malignant soft tissue neoplasms. Traumatic neuroma, Morton neuroma, lipomatosis of a nerve, nerve sheath ganglion, perineurioma, benign and malignant peripheral nerve sheath tumors (PNST) are included in this group of pathologies.     

From the archives of the AFIP. Imaging of musculoskeletal neurogenic tumors: radiologic-pathologic correlation.

Numerous neurogenic tumors can affect the musculoskeletal system, including traumatic neuroma, Morton neuroma, neural fibrolipoma, nerve sheath ganglion, neurilemoma, neurofibroma, and malignant peripheral nerve sheath tumors (PNSTs). The diagnosis of neurogenic tumors can be suggested from their imaging appearances, including lesion shape and intrinsic imaging characteristics. It is also important to establish lesion location along a typical nerve distribution (eg, plantar digital nerve in Morton neuroma, median nerve in neural fibrolipoma, large nerve trunk in benign and malignant PNSTs). Traumatic and Morton neuromas are commonly related to an amputation stump or are located in the intermetatarsal space, respectively. Neural fibrolipomas show fat interspersed between nerve fascicles and are often associated with macrodactyly. Nerve sheath ganglion has a cystic appearance and commonly occurs about the knee. Radiologic characteristics of neurilemoma, neurofibroma, and malignant PNST at computed tomography (CT), ultrasonography, and magnetic resonance imaging include fusiform shape, identification of entering and exiting nerve, low attenuation at CT, target sign, fascicular sign, split-fat sign, and associated muscle atrophy. Although differentiation of neurilemoma from neurofibroma and of benign from malignant PNST is problematic, recognition of the radiologic appearances of neurogenic tumors often allows prospective diagnosis and improves clinical management of patients.     

Sonographic characteristics of peripheral nerve sheath tumors

OBJECTIVE: We have found variability in the sonographic appearance of peripheral nerve sheath tumors. The purpose of this study was to characterize the sonographic appearances of pathologically proven peripheral nerve sheath tumors. CONCLUSION: Peripheral nerve sheath tumors are often hypoechoic with posterior acoustic enhancement and so may simulate a ganglion cyst. The presence of intrinsic blood flow on color Doppler sonography and peripheral nerve continuity suggests the diagnosis of peripheral nerve sheath tumor. Sonography cannot reliably distinguish neurofibromas from schwannomas.     

Plurifocal malignant peripheral nerve sheath tumor demonstrated by <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography

Malignant peripheral nerve sheath tumors (MPNSTs) are sarcomas that derive from peripheral nerves or from cells associated with the nerve sheath. Magnetic resonance imaging is the main diagnostic imaging modality for evaluating MPNSTs. Computed tomography (CT) of the chest is the main imaging modality used to screen for distant disease, and bone scanning is considered useful for identifying selected metastases. Fluorodeoxyglucose positron emission tomography (FDG-PET) has been useful for differentiating malignant nerve sheath tumors from benign lesions and appears to be able to forecast prognosis. We report a case of a patient with neurofibromatosis 1 (NF1) with a histological diagnosis of MPNST, which was diagnosed by biopsy of a posterior right thigh mass examined by ¹⁸F-FDG-PET/CT.     

Imaging of peripheral nerve sheath tumors with pathologic correlation: pictorial review

Peripheral neurogenic tumors include neurilemoma, neurinoma, and malignant peripheral nerve sheath tumors. All neurogenic tumors share common imaging features. Although differentiation between them is difficult, neurogenic origin can be suggested from their imaging appearances, including fusiform shape, relation to the nerve, "split-fat" sign, associated muscle atrophy and intrinsic imaging characteristics including "target sign" as well as from lesion location along a typical nerve distribution. Our purpose is to make an overview of imaging findings of each type of peripheral nerve sheath tumor with emphasis on characteristic signs and correlate with histologic features. Morton's neuroma and intraneural ganglion are also included as tumors of nerve origin.     

Nerve sheath tumors: evaluation with CT and MR imaging.

Tumors of nerves are classified into benign (schwannoma and neurofibroma) and malignant nerve sheath tumors. Schwannomas almost always occur as solitary lesions, whereas neurofibromas may occur alone or in a greater number, especially in patients with the peripheral form of von Recklinghausen's disease. Benign nerve sheath tumors often present as asymptomatic, slowly growing soft tissue masses. Although malignant nerve sheath tumors are relatively rare, a sudden increase in the size of a lesion, in particular in a patient with neurofibromatosis, should raise the suspicion of malignant change. On computed tomography (CT) and magnetic resonance imaging (MR) a benign nerve sheath tumor usually appears as a well-defined, oval, spherical or fusiform mass with smooth borders and distinct outlines, located in the subcutaneous tissue or centered at the expected anatomic location of a nerve, with displacement of adjacent soft tissues. Generally nerve sheath tumors have a low density on unenhanced CT scans. On MR they are isointense to muscle on T1-weighted images, whereas on T2-weighted images the signal intensity is high. Both on CT and MR the degree of contrast enhancement is moderate to marked and may be homogeneous or inhomogeneous. MR has become the method of choice for evaluating the anatomic location, contour, and relation of a nerve sheath tumor to adjacent neural, vascular, and muscular structures. The imaging criteria for malignant nerve sheath tumors are not specific enough to distinguish them from other malignant soft tissue tumors, so that neither CT nor MR can establish a definite diagnosis.     

Schwannoma in neurofibromatosis type 1: a pitfall for detecting malignancy by metabolic imaging

Neurofibromatosis type 1 (NF1) is a neurocutaneous syndrome characterized by the development of multiple peripheral nerve sheath tumors, the majority of which are benign neurofibromas. However, malignant peripheral nerve sheath tumors (MPNSTs) occur with a 10 % lifetime risk in patients with NF1, often developing within a neurofibroma. When clinical suspicion for an MPNST arises, imaging with FDG PET and MRI is performed to characterize a peripheral tumor for potential malignancy. In this report, we describe a patient with NF-1 who had two peripheral tumors with similar features by PET, both suspicious for MPNST, but differing features by MRI, one of which was subsequently determined to be an MPNST and the second to be a schwannoma.     

Imaging of Soft Tissue Neoplasms in the Adult: Benign Tumors

This discussion reviews the spectrum of benign soft tissue tumors usually found in adults. Lesions most commonly identified in the pediatric population, tumorlike masses, and malignant tumors are discussed in other articles in this issue. Rather than presenting a complete review, the focus of this article is on benign tumors in which the diagnosis may be confidently made or strongly suggested on the basis of imaging. Diagnoses presented include those for lipoma, lipoma variants, giant cell tumor of the tendon sheath, pigmented villonodular synovitis, superficial and deep fibromatoses, elastofibroma, and peripheral nerve sheath tumors.     

外周性神经源性肿瘤的MRI表现与病理基础研究

目的　分析外周性神经源性肿瘤的MRI表现。方法　对 2 5例神经源性肿瘤 (良性 19例 ,恶性 6例 )进行组织学观察 ,分析其与MR表现之间的关系及良恶性肿瘤的MRI鉴别诊断。结果　神经鞘瘤 14例 ,神经纤维瘤 5例 ,恶性周围性神经鞘瘤 (MP NST) 5例 ,原始神经外胚层瘤 1例。起源于神经干的肿瘤常呈纺锤形 ;肿瘤信号多欠均匀 ,T2 WI呈“靶征”者 3例 ,2例神经鞘瘤靶心有较多纤维组织 ,靶周明显水肿、粘液变性 ,1例MPNST靶心有较多纤维组织和部分钙化。 2例MPNST破坏骨质。结论　肿瘤的部位、形态和信号对诊断有较大帮助 ,恶性肿瘤可伴灶周水肿并可破坏邻近骨质。     

Magnetic resonance imaging of malignant soft tissue neoplasms in the adult

This review addresses the spectrum of malignant soft tissue tumors frequently found in adults. Rather than presenting a complete review, the focus of this discussion is on common lesions or lesions in which the diagnosis may be suggested on the basis of imaging. Diagnoses covered include undifferentiated high-grade pleomorphic sarcoma, fibrosarcoma, dermatofibrosarcoma protuberans, liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumor, clear cell sarcoma, hemangioendothelioma, hemangiopericytoma, angiosarcoma, and leiomyosarcoma.