Limb schwannoma: Factors for postoperative neurologic deficit and poor functional results

INTRODUCTION

Neurologic complications after limb schwannoma resection are not unusual, but there is no consensus on risk factors for neurologic deficit or poor functional results. We therefore conducted a retrospective study, to screen for factors predicting, firstly, postoperative neurologic deficit and, secondly, poor functional results.

HYPOTHESIS

Certain pre- and intraoperative features predict risk of failure, poor results or aggravation.

PATIENTS AND METHODS

A single-center retrospective study was conducted in the University Hospital of Lille, France, for the period January 2004 to March 2020, including 71 patients. Preoperative variables (gender, age, symptoms, progression, tumor location and size) and operative data (type of surgery) were collected as possible risk factors for postoperative sensory deficit (Weber) and/or motor deficit [Medical Research Council (MRC)] and poor functional result [Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH); Lower Extremity Functional Scale (LEFS) and douleur neuropathique (neuropathic pain) 4 (DN4)].

RESULTS

Results were assessed a mean 69.4±38.5 months' follow-up (range, 6-180 months). In total, 21 patients (29.6%) had deficits (21 sensory, 1 motor) preoperatively and 25 patients (35.2%) postoperatively (20 sensory, 9 motor) (p=0.689). Fourteen patients (19.7%) showed functional aggravation. Fascicular resection was associated with risk of postoperative deficit [OR = 4.65 (95% CI: 1.485-15.543); p=0.004] and functional deterioration [OR = 3.9 (95% CI: 1.143-13.311); p=0.042]. Thirteen patients (18.3%) showed no improvement on DN4. Preoperative pain was a factor for improvement on DN4 [OR = 3.667 (95% CI: 1.055-12.738); p=0.0409].

DISCUSSION

The study identified fascicular resection as a risk factor for postoperative deficit and functional deterioration after limb schwannoma resection. Patients with preoperative neuropathic pain showed alleviation. Resection should be precise, under magnification, avoiding fascicular resection. Preoperative patient information is essential.

LEVEL OF EVIDENCE

IV; retrospective series.

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.

Pseudoprogression of Malignant Peripheral Nerve Sheath Tumor in Patient with Neurofibromatosis Type 1, a Case Report

Pseudoprogression, defined as the radiographic false appearance of disease progression, is not frequently observed in patients with malignant peripheral nerve sheath tumor (MPNST). We report on a case of a patient with neurofibromatosis type 1 (NF1) MPNST pseudoprogression that presented as suspected local recurrence 9.5 years after last treatment. The patient underwent surgical resection following growth of a mass on sequential MRI imaging; surgical pathology, however, showed skeletal muscle with atrophy, fibroadipose tissue, and fat necrosis, without any evidence of tumor. As MPNST survival rates increase, physicians should consider pseudoprogression as a potential presentation after prior treatment.

Clinical Features, Natural History, and Outcomes of Intraneural Perineuriomas: A Systematic Review of the Literature

BACKGROUND

Intraneural perineurioma is a rare peripheral nerve sheath tumor characterized by localized proliferation of perineurial cells. The literature consists predominantly of case reports and institutional series, with inconsistent and confusing nomenclature. We present a pooled analysis of all reported cases of intraneural perineurioma in the literature.

METHODS

A systematic search of PubMed, MEDLINE, Embase, and Scopus was performed according to PRISMA guidelines to identify all reported cases of intraneural perineurioma in the literature. Individual cases were pooled and analyzed for demographics, clinical features, and outcomes.

RESULTS

A total of 172 cases were identified across 72 studies, of which 149 were found in major peripheral nerves and their branches. Median age of patients at diagnosis and onset of symptoms was 18 years (interquartile range [IQR], 12-34 years) years and 13.5 years (IQR, 8-26 years), respectively, with 54.4% (81/149) being female. The most common sites were the sciatic nerve or its branches (41.9%), median nerve (13.5%), radial nerve (12.2%), and brachial plexus (12.2%). Most patients were managed conservatively (52.9%; 72/136). Among those managed conservatively with available follow-up (n = 31), median follow-up was 11 months, and most (67.7%, n = 21) reported no change in neurologic status, although worsening was noted in 29.0% (9/31). Among surgically managed cases (n = 64), the most common intervention was resection with or without repair (62.5%; 40/64), neurolysis (25%; 16/64), or tendon transfers without resection (12.5%; 8/64). No lesion recurred after surgical resection.

CONCLUSIONS

Intraneural perineurioma represents a benign focal lesion presenting with weakness and atrophy affecting adolescents and young adults. Most cases are managed nonoperatively and surgical treatment strategies are varied.

Intraneural perineurioma of the median nerve at the elbow: A clinical case

A 31-year-old female patient presented with swelling on the anteromedial aspect of her right elbow with a sensory deficit in the median nerve territory. Biopsies led to the diagnosis of intraneural perineurioma (INP). Surgical excision was performed and followed by an intercalary graft. INP is a rare benign tumor of the peripheral nerves characterized by a multiplication of perineural cells invading the endoneurium. This lesion is often unknown, under-diagnosed, and its treatment is poorly defined. Few cases have been described in the literature; the majority involve the median nerve at the wrist and no references have been found about its localization to the median nerve at the elbow.

Response to combined BRAF/MEK inhibition in adult BRAF V600E mutant spinal pilocytic astrocytoma

Pilocytic astrocytomas are World Health Organisation (WHO) grade I tumors, occurring predominantly supratentorially and in the pediatric population. Although the mainstay of treatment is local therapies such as surgery, targeted systemic therapies may be necessary for recurrent or unresectable disease. The majority of sporadic pilocytic astrocytomas are associated with the BRAF-KIAA fusion gene, which results in constitutive activation of the MAP Kinase pathway. Less frequently, the BRAF V600E point mutation has been described, occurring in less than 10% of supratentorial pilocytic astrocytomas. Tumours with this mutation may respond to targeted therapy against the BRAF/MAP Kinase pathway. We report the first described case of a spinal pilocytic astrocytoma in an adult patient with a BRAF V600E mutation responding to targeted therapy using BRAF and MEK tyrosine kinase inhibitors, and share our experiences with the management of toxicity in this patient population.

Novel approach to continuous neurophysiological monitoring during surgery of peripheral nerve tumors

Background:

Intraoperative neurophysiological monitoring (IONM) with nerve action potential (NAP) can be useful during peripheral nerve surgery. However, current methodologies are not optimized for continuous recording of the NAP. The use of newer electrodes may make it possible to more conveniently obtain continuous recordings of the NAP during surgery.

Methods:

After localizing the nerve of interest and dissecting it from the adjacent soft tissue, two APS^® (Automatic Periodic Stimulation) electrodes, originally designed for stimulation of the vagus nerve during thyroid surgery, are placed on the nerve on either sides of the tumor for stimulation and recording using two subdermal electroencephalogram (EEG) needles as anode and reference, respectively. Both monopolar and bipolar recordings can be used as appropriate. Anesthesia regime comprised sevoflurane or total intravenous anesthesia (TIVA). No muscle relaxant after intubation, local anesthesia, or blood pressure cuff is used during the surgery.

Results:

Twelve patients (6 male, 6 female) with peripheral nerve tumors (motor, sensitive, or mixed nerves) or tumors affecting the peripheral nerves were monitored in our center since 2014 (mean age: 50 years; 28–79). In 10 patients, the NAP was monitored without experiencing any changes from the beginning till the end of the surgery; in these patients, no postoperative deficit was adverted. In the last 2 patients, who departed from a complete neurological deficit, no NAP was recorded at the baseline or during the surgery, and they did not experience any neurological improvement.

Conclusion:

The vagus nerve stimulation electrodes open new possibilities in peripheral nerve IONM. We have used them for continuous monitoring without additional problems with the traditional probes.

Paediatric Extracranial Spinal Accessory Nerve Schwannoma: An Extremely Rare Case Report

Schwannoma in head and neck region are quiet common and generally arise from last four cranial nerves. Spinal accessory nerve involvement is very rare. We are hereby presenting an extremely rare case of paediatric XI nerve schwannoma hitherto unreported in English medical literature till date.

A giant solitary schwannoma of the arm mimicking cyst hydatid

We present a 77-year-old female with a size of 9.5×9×7 cm³ giant schwannoma of musculocutaneous nerve volarly located in midarm, which was misdiagnosed as cyst hydatid on ultrasonographic and magnetic resonance image examination. There was not any neurologic sequele after the operation. In case of the similarity of their clinical and radiological findings, schwannoma should be included in the differential diagnosis of hydatid cysts especially in endemic countries.