Role of sonography in the preoperative assessment of neurilemmoma

An unusual cause of tarsal tunnel syndrome: Schwannoma of the posterior tibial nerve; a rare cause and rare localization

INTRODUCTION

Schwannoma of the posterior tibial nerve is extremely rare.

CASE PRESENTATION

A 25-year-old female with a one-year history of left foot pain is presented. Clinical and radiological findings were in favor of a tarsal tunnel syndrome caused by a schwannoma of the posterior tibial nerve, prompting the patient to undergo surgery. We performed a complete excision of the tumor with the aid of a loupe magnification. At the last follow-up, the patient did well, with no recurrent pain and no neurological squeals.

DISCUSSION

The diagnosis of a tibial nerve schwannoma can often be difficult as, in the early stages, a mass may not be palpable and symptoms are often non-specific because of the slow-growing soft tissue mass.

CONCLUSION

Although schwannoma is a rare cause of tarsal tunnel syndrome, it should be kept in mind by physicians, especially in cases of chronic unexplained foot pain with a positive Tinel's test.

Schwannoma of the Posterior Tibial Nerve Presenting as Tarsal Tunnel Syndrome: A Case Report with Emphasis on the Role of Microscope during Surgery

Schwannoma is a benign, noninvasive tumour of the peripheral nerve sheath with rare occurrence in the extremities. We present a case of a schwannoma in the posterior tibial nerve which presented with symptoms suggestive of tarsal tunnel syndrome. The patient was managed with surgical excision of the tumour under microscope, and the diagnosis was confirmed by histopathology. Such a presentation is rare, and our case report adds light regarding the management of such cases.

Sonographic Features and Diagnosis of Peripheral Schwannomas

BACKGROUND

To determine the sonographic features of peripheral schwannomas.

METHODS

This retrospective study included 54 cases of schwannoma in 51 patients. Ultrasonography (US) and MRI were performed in all patients. The US features of each tumor were analyzed and compared with pathologic findings. The US target sign was compared with the MRI findings.

RESULTS

On US, 53 of the 54 schwannomas had a regular shape and clear margins, and one had an irregular shape. Thirty-seven of the 54 schwannomas were categorized as solid, 16 as cystic and solid, and one as entirely cystic; distal sound enhancement was associated with 47 schwannomas. The target sign was seen in 24, the rat tail sign in 28, the vessel accompanying sign in 22, and the split fat sign in 5. The entering and exiting nerves were situated centrally in 9 and eccentrically in 19 schwannomas. Vascularity on color Doppler imaging using a 0 to III scale was graded 0 in 4 schwannomas, I in 10, II in 26, and III in 14. Twenty-four target signs were detected in 54 schwannomas by US, and 28 were detected by MRI. There was good agreement between the target signs noted on US and those seen on MRI (κ = 0.631, p < 0.001).

CONCLUSIONS

The sonographic diagnosis of peripheral schwannomas is feasible and reliable. The target sign is a prominent US feature in peripheral schwannomas, comparable to that observed with MRI. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:127-133, 2017.

Sonographic Differentiation Between Schwannomas and Neurofibromas in the Musculoskeletal System

OBJECTIVES

The purpose of this study was to determine key features and define a strategy for differentiation between schwannomas and neurofibromas using sonography.

METHODS

This retrospective study was approved by the Institutional Review Board at our hospital, and informed consent was waived. We reviewed sonograms of pathologically proven schwannomas and neurofibromas of the extremities and body wall. On grayscale images, tumors were evaluated on the basis of their size, maximum-to-minimum diameter ratio, shape, contour, margin, location, encapsulation, echogenicity, echo texture, cystic changes, presence of intratumoral calcifications, presence of a target sign, and presence of an entering or exiting nerve. If an entering or exiting nerve was identified, the nerve-tumor position and nerve-tumor transition were characterized. On color Doppler images, the presence and amount of vascularity were evaluated. Student t tests were used for analysis of continuous variables (size, maximum-to-minimum diameter ratio, and age); χ(2) and Fisher exact tests were used for analysis of categorical variables.

RESULTS

A total of 146 pathologically proven tumors, including 115 schwannomas and 31 neurofibromas of the extremities and body wall, were included. The maximum diameter, maximum-to-minimum diameter ratio, contour, cystic portion, nerve-tumor position, nerve-tumor transition, and vascularity were significantly different in schwannomas versus neurofibromas (P < .05), and a lobulated contour, fusiform shape, and hypovascularity of neurofibromas could be helpful for differentiation when a prediction model is considered. The nerve-tumor position, nerve-tumor transition, and maximum-to-minimum diameter ratio were also significantly different between groups (P < .05) and thus could be useful for differentiation of neurogenic tumors.

CONCLUSIONS

Sonographic findings are helpful in differentiating between schwannomas and neurofibromas.

Schwannomas of the upper extremity: analysis of 34 cases

BACKGROUND

Schwannomas are the most common benign tumours developing in peripheral nerves. They usually present as a slow-growing mass, sometimes associated with pain and paraesthesia. The aim of this study is to define the correct preoperative diagnosis, to review the surgical treatment employed and to evaluate short- and long-term neurological deficits.

METHODS

Thirty-four patients affected by schwannoma in the upper limbs were treated in the period 1995-2011. In 15 patients the tumour was located on the ulnar nerve, in 8 on the median nerve, in 2 on the radial nerve, in 1 on the anterior interosseous nerve, in 1 on the muscle-cutaneous nerve, and in the remaining 7 on the digital nerves. All patients were surgically treated using a microsurgical approach.

RESULTS

The enucleation of the mass was possible without fascicle lesion in 12 cases. In 22 cases resection of the indissociable fascicles was performed. Postoperative paraesthesia was present in 28 out of 34 treated patients; this clinical sign regressed in a mean period of 12 months in 27 patients.

CONCLUSIONS

When approaching a palpable mass in the upper limbs, the possibility of a peripheral nerve tumour should always be considered. It is important to look for typical signs of schwannomas, such as a positive Tinel sign and peripheral paraesthesia. Imaging assessment with magnetic resonance imaging (MRI) and ultrasonography enables the determination of where the tumour takes its origin and from which nerve. Microsurgical techniques and know-how are recommended in approaching the resection in order to respect as many nerve fibres as possible.

Ultrasound-Guided Needle Localization of the Saphenous Nerve for Removal of Neuroma in the Infrapatellar Branches

Background:

Neuromata formation in the infrapatellar branch of the saphenous nerve (IPBSN) has been well described as a potential complication of arthroscopic knee surgery and knee trauma. Resection has been proven to provide improvement of pain and increased range of motion. Currently, physical examination and surgical exploration based on anatomic landmarks are the standard for intraoperative localization of IPBSN neuromas.

Objective:

To demonstrate the anatomy of the IPSBN and the use of preoperative ultrasound and needle placement for localization of the nerve before sectioning.

Methods:

Using both anatomic dissections and the combination of preoperative ultrasound and curved-needle placement, we demonstrate the technical nuances to localize the IPBSN before operative section.

Results:

Cadaveric dissection is used to illustrate the main trunk of the IPSBN and its branches. In 2 cases, ultrasound guidance was effectively used to localize the saphenous nerve and its branches and facilitate the operative treatment of patients with symptomatic IPBSN neuromas.

Conclusion:

Ultrasound is a widely accepted and commonly utilized imaging modality; however, in this report, ultrasound-guided needle localization was used to aid in the resection of neuromas of small, painful sensory nerves.

Schwannoma of the median nerve at the wrist and palmar regions of the hand: a rare case report

Schwannomas are also known as neurolemmas that are usually originated from Schwann cells located in the peripheric nerve sheaths. They are the most common tumours of the hand (0.8-2%). They usually present solitary swelling along the course of the nerve however multiple lesions may be present in cases of NF type 1, familial neurofibromatosis, and sporadic schwannomatosis. Schwannomas are generally represented as an asymptomatic mass; however pain, numbness and fatigue may take place with the increasing size of the tumour. EMG (electromyelography), MRI (magnetic resonance imagination), and USG (ultrasound) are helpful in the diagnosis. Surgical removal is usually curative. In this paper, we present a 24-year-old male referred to our clinic for a lump located at the volar side of the left wrist and a lump located in his left palm and numbness at his 3rd and 4th fingers. Total excision was performed for both lesions. Histopathological examination of the masses revealed typical features of schwannoma. At the 6th-month followup the patient was symptom-free except for slight paresthesia of the 3rd and the 4th fingers. For our knowledge, this is the second case in the literature presenting wrist and palm involvement of the median nerve schwannoma.

Evidence-based guideline: neuromuscular ultrasound for the diagnosis of carpal tunnel syndrome

INTRODUCTION

The purpose of this study was to develop an evidence-based guideline for the use of neuromuscular ultrasound in the diagnosis of carpal tunnel syndrome (CTS).

METHODS

Two questions were asked: (1) What is the accuracy of median nerve cross-sectional area enlargement as measured with ultrasound for the diagnosis of CTS? (2) What added value, if any, does neuromuscular ultrasound provide over electrodiagnostic studies alone for the diagnosis of CTS? A systematic review was performed, and studies were classified according to American Academy of Neurology criteria for rating articles of diagnostic accuracy (question 1) and for screening articles (question 2).

RESULTS

Neuromuscular ultrasound measurement of median nerve cross-sectional area at the wrist is accurate and may be offered as a diagnostic test for CTS (Level A). Neuromuscular ultrasound probably adds value to electrodiagnostic studies when diagnosing CTS and should be considered in screening for structural abnormalities at the wrist in those with CTS (Level B).

Surgical outcome of schwannomas arising from major peripheral nerves in the lower limb

PURPOSE

The treatment of symptomatic Schwannoma is surgical excision. However, in the case of major peripheral nerves with motor function, there are concerns including neurological complications following surgery. This study was designed to evaluate the surgical outcome of Schwannomas originating from major peripheral nerves of the lower limb. Additionally, we sought to find out the predictable factors for permanent neurological deficits.

METHODS

Between 2004 and 2008, 30 consecutive Schwannomas underwent simple excision or enucleation. Surgical outcomes after excision were evaluated with an emphasis on neurological deficits and recurrence. Neurological complications were classified as major or minor neurological deficits and evaluated immediately after surgery and at final follow-up. Risk factors for development of neurological deficits were identified.

RESULTS

Twenty-three patients (23/30, 76.7 %) developed neurological deficits immediately after surgery. After a mean of 58.8 months (32-79 months), 19 patients (19/30, 63.3 %) showed no residual neurological deficits. Among the remaining 11 (11/30, 36.7 %), nine patients had tolerable symptoms and two patients had major neurological deficits including significant motor weakness and sensory impairments. Larger tumours tended to be at greater risk of neurological deficit after surgery. One recurrence of the tumour was seen two years after surgery. There were no cases of reoperation or malignant transformation

CONCLUSIONS

In the majority of cases, Schwannomas in the lower limb can be excised with acceptable risk for neurological deficits. However, meticulous dissection is required in large-sized Schwannomas because these tumours seem to have a higher frequency of fascicular injury during dissection.

Neurilemmoma of the first branch of the lateral plantar nerve causing tarsal tunnel syndrome

In this article, the authors report a case of tarsal tunnel syndrome caused by neurilemmoma of the first branch of the lateral plantar nerve, with symptom resolved after excision. A 42-year-old man presented with left medial heel pain radiating to the lateral sole for 6 months. On examination, there was positive Tinel sign over the medial heel with pain radiating to the lateral sole. Ultrasonography and magnetic resonance imaging confirmed the presence of a 1-cm neurogenic tumor inside the tarsal tunnel. Intraoperatively, a 1-cm neurilemmoma was found at the first branch of the lateral plantar nerve inside the tarsal tunnel. The lesion was excised completely with preservation of its fascicle. The symptom resolved completely after the operation.

Sonographic diagnosis of a cervical vagal schwannoma

This case report illustrates the role of high-resolution sonography in the preoperative assessment of a schwannoma of the vagus nerve in the neck. Sonography identified the tumor in the right carotid space and determined its origin from the right vagus nerve, facilitating the surgeon's approach to preserve nerve function.

Intraneural hemangioma of the median nerve: A case report

Hemangiomas of the median nerve are very rare and, so far, only ten cases of intraneural hemangioma of this nerve have been reported in the literature. We present a case of 14-year-old girl who had a soft tissue mass in the region of the left wrist with signs and symptoms of carpal tunnel syndrome. Total removal of the mass was achieved using microsurgical epineural and interfasicular dissection. The symptoms were relieved completely, after this procedure, without any neurologic deficit. On follow-up two years later, no recurrence was observed. Whenever a child or young adult patient presents with CTS the possibility of a hemangioma involving the median nerve should be kept in mind in the differential diagnosis.

Ultrasound in the diagnosis of a median neuropathy in the forearm: case report

Background

Electrodiagnostic studies are traditionally used in the diagnosis of focal neuropathies, however they lack anatomical information regarding the nerve and its surrounding structures. The purpose of this case is to show that high-resolution ultrasound used as an adjunct to electrodiagnostic studies may complement this lack of information and give insight to the cause.

Case presentation

A 60-year-old male patient sustained a forearm traction injury resulting in progressive weakness and functional loss in the first three digits of the right hand. High-resolution ultrasound showed the presence of an enlarged nerve and a homogenous soft-tissue structure appearing to engulf the nerve. The contralateral side was normal. Surgery revealed fibrotic bands emanating from the flexor digitorum profundus muscle compressing the median nerve thus confirming the ultrasound findings.

Conclusion

A diagnostically challenging case of median neuropathy in the forearm is presented in which high-resolution ultrasound was valuable in establishing an anatomic etiology and directing appropriate management.

The clinical applications of peripheral nerve imaging in the upper extremity

Use of different imaging modalities in the diagnosis of peripheral nerve pathology has been growing steadily. This review attempts to summarize their use, particularly with regard to ultrasound and magnetic resonance imaging, and their practical applications in the clinical setting.

Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis

Schwannomas are the most common tumours of the sheath of peripheral nerves. The clinical diagnosis is usually straightforward, but may be delayed for many years in a schwannoma of the posterior tibial nerve. The symptoms are often attributed to entrapment neuropathy or to lumbosacral radiculopathy. We describe 25 patients with a schwannoma of the posterior tibial nerve. Only three were diagnosed within a year of presentation. The mean time to diagnosis was 86.5 months with a median of 48 months (2 to 360). All the patients complained of pain, which was felt specifically in the sole of the foot in 18. A Tinel sign was detected in all 25 patients. MRI confirmed the diagnosis in all the cases in which it had been undertaken. Surgical resection of the lesion abolished the neuropathic pain. In patients with a long history of neuropathic pain in the lower limb in whom lumbar and pelvic lesions have been excluded, a benign tumour of the sheath of a peripheral nerve may explain the symptoms. Surgical resection of the tumour is safe and effective.

Acute median nerve palsy due to hemorrhaged schwannoma: case report

Schwannomas are common, benign nerve tumors originating from the sheath of peripheral nerves. In this article, a 54 year old woman suffered from sudden onset motor and sensory deficit at her first radial three fingers on her right hand. Radiological investigations were normal. Electromyography diagnosed a median nerve entrapment neuropathy and urgent surgery was performed. Interestingly, a hemorrhaged mass was detected in the median nerve at the proximal end of the carpal ligament and was resected totally. Histopathological diagnosis was Schwannoma. The patient maintained a healthy status for five years.