Vertebral artery is an anatomical landmark in the posterior unilateral resection of cervical benign nerve sheath tumors with dumbbell extension of Eden type 2 or 3

Background

In the cervical nerve sheath tumor (NST) surgery with dumbbell extension of Eden type 2 or 3, selection of anterior, posterior, or combined approach remains controversial.

Objectives

This technical note aimed to propose possible advantages of the posterior unilateral approach (PUA). Methods: Six patients who underwent the surgical treatment of cervical NSTs with dumbbell extension of Eden type 2 or 3 were included. The critical surgical steps included (1) complete separation of extradural and intradural procedures, (2) careful peeling of the neural membranes (epineurium and perineurium) from the tumor surface in the extradural procedure, (3) complete removal of the extradural tumor within the neural membranes, (4) intradural disconnection of tumor origin, and (5) intentional tumor removal up to the vertebral artery (VA), i.e., the VA line.

Results

The tumor location of dumbbell extension was Eden types 2 and 3 in two and four patients. Gross total resection was achieved in two patients and intentional posterior removal of the tumor to the VA line was achieved in the remaining four patients. No vascular or neural injuries associated with surgical procedures occurred. Postoperative neurological assessment revealed no symptomatic aggravation in all patients. No secondary surgery was performed during the study period.

Conclusion

PUA was safe and less invasive for functional recovery and tumor resection, if the anatomical relationship between the tumor and VA is clearly understood. The VA line is an important anatomical landmark to limit the extent of tumor resection.

Preoperative Wire Localization: A Simple Guidance Technique for Excision of Deep, Painful, Small, Soft Tissue Neurofibromas

A novel use of preoperative wire localization to aid in the removal of small deep-seated soft tissue nerve sheath tumors is described. Wire localization is commonly used in breast surgery, and applying this technique in neurosurgery will enable the surgeon to directly reach the lesion with smaller incisions and prevent unnecessary soft tissue dissection.

Nerve Fiber Immunohistochemical Panel Discriminates between Nerve Sheath and Perivascular Wall Tumors

Benign and malignant nerve sheath tumors (NST) pose a major challenge in routine diagnostic anatomic pathology because of shared histomorphological features with other soft-tissue tumors (STT). As a result, NST are often diagnosed as STT, a broad category that encompasses various entities including perivascular wall tumors (PWT) and that represents approximately 15% of all skin tumors in dogs. Immunohistochemistry (IHC) can assist the identification of histologic subtypes of STT. This IHC pilot study applies various markers largely expressed by peripheral nerves to twelve benign and six malignant NST and determines the intratumoral protein expression of laminin, periaxin-1, Sox-10 and S-100 in the NST subtypes. Furthermore, this study assesses the usefulness of peripheral nerve markers applied to diagnostic work cases and demonstrates the relevance of laminin expression patterns, periaxin-1 and Sox-10 in assisting the differentiation of NST from other STT, in particular from PWT.

Robotic Nerve Sheath Tumor Resection With Intraoperative Neuromonitoring: Case Series and Systematic Review

BACKGROUND

Retroperitoneal nerve sheath tumors present a surgical challenge. Despite potential advantages, robotic surgery for these tumors has been limited. Identifying and sparing functional nerve fascicles during resection can be difficult, increasing the risk of neurological morbidity.

OBJECTIVE

To review the literature regarding robotic resection of retroperitoneal nerve sheath tumors and retrospectively analyze our experience with robotic resection of these tumors using a manual electromyographic probe to identify and preserve functional nerve fascicles.

METHODS

We retrospectively analyzed the clinical courses of 3 patients with retroperitoneal tumors treated at the National Institutes of Health by a multidisciplinary team using the da Vinci Xi system. Parent motor nerve fascicles were identified intraoperatively with a bipolar neurostimulation probe inserted through a manual port, permitting tumor resection with motor fascicle preservation.

RESULTS

Two patients with neurofibromatosis type 1 underwent surgery for retroperitoneal neurofibromas located within the iliopsoas muscle, and 1 patient underwent surgery for a pelvic sporadic schwannoma. All tumors were successfully resected, with no complications or postoperative neurological deficits. Preoperative symptoms were improved or resolved in all patients.

CONCLUSION

Resection of retroperitoneal nerve sheath tumors confers an excellent prognosis, although their deep location and proximity to vital structures present unique challenges. Robotic surgery with intraoperative neurostimulation mapping is safe and effective for marginal resection of histologically benign or atypical retroperitoneal nerve sheath tumors, providing excellent visibility, increased dexterity and precision, and reduced risk of neurological morbidity.

Voluminous Laryngeal Schwannoma Treated with Endoscopic Laser Approach

Laryngeal schwannomas are rare benign encapsulated neurogenic tumors that represent less than 1.5% of all benign laryngeal tumors. We report a case of voluminous laryngeal schwannoma that was incidentally found during endotracheal intubation for thyroidectomy in a 43-year-old woman with clinical findings, features of radiologic and histopathologic examinations. The tumor was removed by CO₂ laser during microlaryngoscopy. In this case report, we present a challenging approach that can be used in diagnosis and treatment of laryngeal schwannomas. Complete removal of the tumor should be considered as the initial approach to minimize morbidity.

Sleeve-Shaped Neurothekeoma of the Ulnar Nerve: A Unique Case of a Still Unclear Pathological Entity

Background: Neurothekeomas are slow-growing, well-circumscribed benign neoplasms. They usually involve cutaneous or subcutaneous tissues. Although originally described as myxomas deriving from nerve sheath cells, their exact histological classification is still uncertain. Peripheral nerve localization is rarely reported. Here, we describe a unique case of sleeve-shaped neurothekeoma of the ulnar nerve, which was incidentally discovered during a cubital tunnel release surgery. Methods: A 57-year-old man was admitted at our institution with clinical, ultrasonographic, and electromyographic findings highly suggestive of cubital tunnel syndrome. During ulnar nerve decompression surgery, however, no bony or ligament compression was noticed, but a segment of the nerve wrapped by a thick sleeve-shaped tissue, which had no clear-cut cleavage plane from the nerve. Given this unexpected finding, the en bloc excision of the lesion was avoided. A nerve decompression with biopsy of the swelling portion of the lesion was performed instead. Results: Histological examination described abundant myxoid stroma, with epithelioid and ring-shaped cells arranged in cords, negative to S100 protein at immunohistochemical analysis. This pattern was suggestive of neurothekeoma. The patient showed improvement in hypermyotrophy and intrinsic weakness of the hand. Conclusions: To the best of our knowledge, this is the first report of a sleeve-shaped neurothekeoma of the ulnar nerve. The exact pathological characterization of such rare entities remains uncertain. In case of peripheral nerve localization, and when a clear cleavage plane is absent, the correct management of these lesions should be that of simple nerve decompression followed by biopsy.

High dose hypofractionated frameless volumetric modulated arc radiotherapy is a feasible method for treating canine trigeminal nerve sheath tumors

The aim of this prospective pilot study was to evaluate the feasibility and effectiveness of curative intent high dose hypofractionated frameless volumetric modulated arc radiotherapy for treatment of canine trigeminal peripheral nerve sheath tumors. Client-owned dogs with a presumptive imaging-based diagnosis of trigeminal peripheral nerve sheath tumor were recruited for the study during the period of February 2010 to December 2013. Seven dogs were enrolled and treated with high dose hypofractionated volumetric modulated arc radiotherapy delivered by a 6 MV linear accelerator equipped with a micro-multileaf beam collimator. The plans were computed using a Monte Carlo algorithm with a prescription dose of 37 Gy delivered in five fractions on alternate days. Overall survival was estimated using a Kaplan-Meier curve analysis. Magnetic resonance imaging (MRI) follow-up examinations revealed complete response in one dog, partial response in four dogs, and stable disease in two dogs. Median overall survival was 952 days with a 95% confidence interval of 543-1361 days. Volumetric modulated arc radiotherapy was demonstrated to be feasible and effective for trigeminal peripheral nerve sheath tumor treatment in this sample of dogs. The technique required few sedations and spared organs at risk. Even though larger studies are required, these preliminary results supported the use of high dose hypofractionated volumetric modulated arc radiotherapy as an alternative to other treatment modalities.

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.

Neuroimaging of spine tumors

Intramedullary, intradural/extramedullary, and extradural spine tumors comprise a wide range of neoplasms with an even wider range of clinical symptoms and prognostic features. Magnetic resonance imaging (MRI), commonly used to evaluate the spine in patients presenting with pain, can further characterize lesions that may be encountered on other imaging studies, such as bone scintigraphy or computed tomography (CT). The advantage of the MRI is its multiplane capabilities, superior contrast agent resolution, and flexible protocols that play an important role in assessing tumor location, extent in directing biopsy, in planning proper therapy, and in evaluating therapeutic results. A multimodality approach can be used to fully characterize the lesion and the combination of information obtained from the different modalities usually narrows the diagnostic possibilities significantly. The diagnosis of spinal tumors is based on patient age, topographic features of the tumor, and lesion pattern, as seen at CT and MRI. The shift to high-end imaging incorporating diffusion-weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy, whole-body short tau inversion recovery, positron emission tomography, intraoperative and high-field MRI as part of the mainstream clinical imaging protocol has provided neurologists, neuro-oncologists, and neurosurgeons a window of opportunity to assess the biologic behavior of spine neoplasms. This chapter reviews neuroimaging of spine tumors, primary and secondary, discussing routine and newer modalities that can reduce the significant morbidity associated with these neoplasms.

Case presentations and review of plexiform schwannoma in the foot

Plexiform schwannoma is a soft tissue tumor that rarely presents in the lower extremity. We have reported on 2 cases of plexiform schwannomas that occurred in the foot and ankle. Owing to the relative obscurity of this condition in the lower extremity, we have also provided an overview of plexiform schwannomas and discussed the differences between this and other suspicious nodular soft tissue masses. The first patient was a 38-year-old female, who had a soft tissue mass located on the lateral aspect of her right foot that became symptomatic. The second patient was an 11-year-old male, who had a symptomatic soft tissue mass on the plantar aspect of his right foot. Both patients underwent surgical excision of the tumor.

Isolated plexiform schwannoma of the hand

BACKGROUND

The plexiform schwannoma, a peripheral nerve sheath tumor, is a very rare entity. But dermatologists should be familiar with since they may be the first who make diagnosis possible by taking a deep biopsy.

MAIN OBSERVATION

A 24-year-old male presented with multiple asymptomatic subcutaneous nodules of the palmar side of his right hand. Histologic investigations revealed a plexiform schwannoma with numerous Antoni-A areas. There was no evidence of neurofibromatosis type 1 or 2.

CONCLUSIONS

Plexiform schwannoma of the hand is a rare nerve sheath tumor. In individual (symptomatic) cases hand surgery is an option that needs a critical indication. In every case histologic investigations are mandatory to confirm the diagnosis and not to overlook the malignant variant of this disease.

Descriptive epidemiology of vestibular schwannomas

Vestibular schwannomas, commonly termed acoustic neuromas, arise from the vestibular branch of the eighth cranial nerve (acoustic nerve) and are benign, slow-growing brain tumors that negatively impact patient quality of life. They are thought to account for the majority of intracranial nerve sheath tumors. To describe incidence rate patterns and trends of primary nerve sheath tumors of the brain/CNS and the subset of vestibular schwannomas in two population-based incidence registries, data were obtained from 11 Central Brain Tumor Registry of the United States (CBTRUS) collaborating state registries and the Los Angeles County Cancer Surveillance Program (LACCSP) (1975-1998). Average annual incidence rates were tabulated by age, gender, race, year, and region and were age-adjusted to the year 2000 U.S. standard population. Multiplicative Poisson regression models were used to compare trends in primary nerve sheath tumors of the brain/CNS overall and in subgroups, including vestibular schwannomas, controlling for age, gender, race, microscopic confirmation, and region. Joinpoint regression analysis was used to identify any sharp changes in incidence over time. The overall incidence of primary nerve sheath tumors of the brain/CNS was 1.1 per 100,000 person-years (CBTRUS, 1995-1999 and LACCSP, 1995-1998). The incidence of vestibular schwannomas was similar for both data sets: 0.6 per 100,000 person-years (CBTRUS, 1995-1999) and 0.8 per 100,000 person-years (LACCSP, 1995-1998). Moreover, the incidence of primary nerve sheath tumors of the brain/CNS overall (CBTRUS, 1985-1999 and LACCSP, 1975-1998) and of vestibular schwannomas (CBTRUS, 1992-1999 and LACCSP, 1992-1998) increased over time. However, the incidence of benign schwannomas in sites other than the acoustic nerve either decreased (CBTRUS, 1992-1999) or experienced no significant change (LACCSP, 1992-1998). While improvements in diagnosis and reporting may explain some of these trends, further consideration of potential etiologic factors may be warranted.