Peripheral Nerve Schwannoma: A Review of Varying Clinical Presentations and Imaging Findings

A schwannoma or neurilemmoma is a benign, isolated, noninvasive, and encapsulated tumor originating from Schwann cells of the peripheral nerve sheath. The incidence of a schwannoma occurring in the foot and ankle is rare, with prevalence rate of 1% to 10%. Schwannomas have no sex predilection, and they commonly occur in patients in their fourth decade. Malignant transformation of benign schwannoma is unusual; however, it is important to note that malignant variants of schwannomas do exist and account for about 5% to 10% of all soft tissue sarcomas. We present 3 cases of benign schwannoma in the lower extremity. All 3 patients presented with varying clinical symptoms, including pain, paresthesia, weakness, and a palpable mass. A schwannoma was eventually diagnosed in all 3 patients. We discuss and review the known entities of peripheral nerve schwannoma and describe the clinical and imaging findings and therapeutic strategies for treating and diagnosing peripheral nerve schwannoma.     

Role of sonography in the preoperative assessment of neurilemmoma

This case report illustrates the role of high-resolution sonography in the preoperative assessment of a neurilemmoma of the median nerve in the forearm. Sonography identified the 3-dimensional localization of the nerve tumor its origin from a nerve fascicle, and its relationship with noninvolved nerve fascicles, facilitating the surgeon's approach to preserve noninvolved fascicles.     

神经鞘瘤假腺性结构的本质

目的：认识神经鞘瘤假腺性结构的本质及其发生原因,决定是否采纳假腺性神经鞘瘤之命名。方法：运用免疫组化ABC法观察126例神经鞘瘤的病理形态表现。结果：颅内和椎管内神经鞘瘤除了具有躯体神经普通型神经鞘瘤的A、B区结构表现外,尚易发生出血、囊性变、核多形性,泡沫细胞和假腺样结构等变化。免疫组化证明这些假腺样或腔隙状结构由神经鞘瘤的瘤细胞组成。对S-100蛋白、MBP呈阳性表达,对EMA和CEA呈阴性表达。结论：神经鞘瘤的假腺样和腔隙状结构和颅内椎管内神经鞘瘤的出血,囊性变,核异形,泡沫细胞等改变一样,可能是在肿瘤的退行性改变中对囊液的反应性改变,以不采用“假腺性神经鞘瘤”为妥。     

Imaging characteristics and surgical management of orbital neurilemmomas

AIM: To review imaging characteristics and surgical outcomes of orbital neurilemmoma. METHODS: Retrospective review of 21 patients with orbital neurilemmoma managed at the Zhongshan Ophthalmic Center of Sun Yat-sen University from June 2005 to December 2016. All patients underwent surgical excision following preoperative imaging including ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI). RESULTS: Among these patients, 11 were male and 10 were female, with age ranging from 12 to 75y (average, 40.3y). Ultrasound of the orbit showed a roundish well-demarcated orbital mass with low or middle internal reflectivity in each case. Dark inner liquid fields were detected in 28.6% of these cases. Doppler ultrasound demonstrated blood flow signals in these masses. CT showed that the tumors were either homogeneous or heterogeneous. MRI of T1WI revealed isointense or hypointense tumors, while the T2WI indicated heterogeneous hyperintense lesions. Gd contrast MRI demonstrated heterogenous or homogeneous enhancement initiating from the wide area of the lesion. Six patients underwent lateral orbitotomy and 15 anterior orbitotomy. All tumors were completely removed. After a mean follow-up of 1.8y, 3 patients experienced reduced vision while the remaining 10 patients showed improved vision after surgery. One patient experienced a mild limitation of upward motility. No recurrence occurred. CONCLUSION: Orbital neurilemmoma is a relatively rare, benign orbital tumor. Effective diagnosis requires a combination of ultrasonography, CT and/or MRI. These imaging techniques are also vital to differentiate neurilemmomas from other orbital masses like that of cavernous hemangiomas and meningiomas. Successful treatment requires complete resection of the neurilemmomas as performed either by lateral or anterior orbitotomy. Recurrence is rare after complete removal.     

后路椎板切除术治疗椎管内神经鞘瘤的疗效观察

目的探讨椎管内神经鞘瘤应用后入路椎板切除术治疗的临床疗效。方法回顾性分析2010年1月至2011年12月间收治的65例椎管内神经鞘瘤行后入路椎板切除术患者的临床资料。结果患者均顺利完成手术,平均手术时间为（2．7±1．0）h,平均出血量为（482．8±114．4）ml。术后5例患者发生脑脊液漏,2例患者麻醉清醒后出现运动功能障碍。术后经1—2年的随访,无一例患者肿瘤复发。治疗后肌力均恢复到4级或5级,差异有统计学意义（P〈0．05）。依据日本骨科协会评估治疗评分标准（JOA）,治疗后患者JOA评分明显高于治疗前,差异有统计学意义（P〈0．05）。结论椎管内神经鞘瘤后人路椎板切除术可充分暴露肿瘤,缩短手术时间,提高临床疗效和肌力,值得临床应用与推广。     

头颈部神经鞘瘤31例临床分析

目的探讨头颈部神经鞘瘤的治疗方法。方法回顾性分析2001年1月～2009年12月收治的31例头颈部神经鞘瘤的临床资料。全部患者均行手术治疗,按是否完整切除肿瘤包膜将其分为完整切除肿瘤包膜组(18例)及部分切除肿瘤包膜组(13例),比较2组的肿瘤复发率、源神经损伤率。结果术后28例患者获随访6个月～8年不等,3例失访(其中完整切除肿瘤包膜组1例,部分切除肿瘤包膜组2例),2组均无复发。术后完整切除肿瘤包膜组并发源神经损伤5例,部分切除肿瘤包膜组无源神经损伤,完整切除肿瘤包膜组源神经损伤率高于部分切除肿瘤包膜组(P<0.05)。结论手术彻底切除肿瘤是治疗头颈部神经鞘瘤最有效的方法。神经鞘瘤包膜是否完整切除,均不影响其预后。在不损伤神经纤维束的前提下,可将神经鞘瘤包膜一并切除。     

Retinoblastoma with low risk for extraocular relapse

Objective: To define a subgroup of patients with retino-blastoma and low risk of extraocular relapse through histopathological and clinical variables. Patients and methods: Inclusion criteria consisted of stage I (intraocular disease), stage IIb1 (without concomitant choroid and/or scleral invasion), and nonenucleated patients (according to the Grabowski-Abramson classification). A total of 112 consecutive patients admitted to Hospital JP Garrahan from 1987 to 1997 were evaluable. Treatment included enucleation or local therapy and no chemotherapy. Results: Forty-one patients had stage Ia (intraretinal), 8 stage Ib (prelaminar optic nerve invasion), 40 stage Ic (uveal invasion), and 12 stage IIb1 (postlaminar optic nerve invasion and cut end free of tumor). Eleven patients had neither eye enucleated. Median follow-up was 60 months. Only two events occurred: one patient had progressive disease in the contralateral globe and died of CNS metastasis and another had an orbital relapse that was successfully treated. Both had choroidal invasion. Five-year pEFS and pOS were 0.97 and 0.98, respectively. Neither length of the optic nerve stump, tumor size, anterior chamber invasion, degree of differentiation, nor degree of ocular coat invasion correlated with increased risk of metastasis. Conclusions: A subset of patients with retinoblastoma with low risk of relapse can be determined using histopathological evaluation of the invasion of ocular coats. Adjuvant chemotherapy is not warranted for patients with intraretinal extension and prelaminar optic nerve invasion. It is also probable that those patients with isolated choroidal invasion and those with postlaminar optic nerve extension with surgical margins clear of tumor do not need chemotherapy.     

马尾神经鞘瘤的临床特点与外科治疗

目的探讨马尾神经鞘瘤的临床特点与外科手术治疗方法。方法回顾性分析2007年6月-2009年3月经手术治疗的32例马尾神经鞘瘤患者的临床症状、影像学改变和外科手术治疗效果。结果多数患者术前出现下肢疼痛麻木的症状(30例),其中18例为双下肢疼痛麻木,体检时25例表现为双侧神经损害或单侧多根神经损害。12例患者首发症状为单纯腰痛。10例误诊为腰椎间盘突出症。6例行CT扫描,但均未能做出正确诊断。所有患者均经MRI确诊,神经鞘瘤表现为圆形或椭圆形病灶,T1加权像呈等或稍低于脊髓信号,T2加权像25例呈不均匀高信号,2例呈稍高信号,5例呈均匀高信号。13例行钆增强扫描,10例呈不均匀强化或环形强化。所有患者均完整切除肿瘤,除1例巨大马尾神经鞘瘤术后症状加重外,其他患者术后功能均改善,短期随访未见复发。结论马尾神经鞘瘤的特征性表现为双下肢疼痛麻木;查体显示双侧或单侧多根神经损伤,但首发症状可不典型;MRI有助于早期诊断;外科手术完整切除肿瘤效果良好。