Cystic schwannomas of the jugular foramen: clinical and surgical remarks

OBJECTIVE: The goals of this report were to outline the clinical presentation, radiological characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for cystic jugular foramen (JF) schwannomas and to describe their differences, compared with solid schwannomas involving the JF. METHODS: A retrospective analysis of radiological studies and surgical records identified five primarily cystic tumors among 21 cases of JF schwannomas that had been surgically treated at our institution. RESULTS: Two types of cystic JF schwannomas were observed, i.e., Type 1 lesions, which are single large cysts with thin ring-like enhancement of the tumor wall, and Type 2 lesions, which are multiple cysts with very irregular, thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improvement in three cases. No deterioration of lower cranial nerve function was observed. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 90). CONCLUSION: Surgical treatment of cystic JF schwannomas can be very demanding because of generally stronger adhesion of the tumor capsule to the surrounding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arachnoidal planes without opening of the cyst and sharp dissection may be useful. Careful intradural opening of the JF should be performed to achieve total removal of the last tumor portion within the JF. A comparison of these lesions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P < 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor postoperative cranial nerve morbidity, especially involving lower cranial nerve function, in the latter cases. Long-term follow-up data failed to demonstrate any significant differences in final patient outcomes, however.     

Trigeminal nerve schwannoma with ancient change. Case report and review of the literature

Ancient change in a schwannoma is a histological variant typically found in longstanding tumors. Histologically, the tumor has biphasic features typical of a schwannoma with evidence of degenerative changes that may complicate diagnosis. The authors report on a 23-year-old man with no features of neurofibromatosis who presented with headaches, blurred vision, and ataxic gait. Magnetic resonance imaging demonstrated a rim-enhancing lesion in the cerebellopontine angle with displacement of brainstem structures and no supratentorial hydrocephalus. Using a lateral suboccipital approach together with image guidance and intraoperative neurophysiological monitoring, a gross-total macroscopic excision was performed. At surgery, the tumor was found to arise from the inferior division of the trigeminal nerve. The final histological diagnosis was schwannoma with ancient change. Note that ancient change in schwannomas is a histological variant thought to result from degenerative changes in longstanding tumors. To the authors' knowledge, this is the first independent report of this histological variant in an intracranial schwannoma.     

Ancient schwannoma of the hand

Ancient schwannoma is a schwannoma subtype, characterized by extensive degeneration and diffuse hypocellular areas. These changes are believed to occur because it takes a long time for ancient schwannomas to develop. Schwannomas with these degenerative changes can be misdiagnosed as sarcomas or other soft-tissue neoplasms. We present a case of a slowly enlarging ancient schwannoma of the thenar area in a 67-year-old woman. The differential diagnosis included atypical soft tissue sarcomas and tumors of neural origin. The combination of ultrasound and magnetic resonance imaging findings provided features that narrowed the differential diagnosis, and histology confirmed the presence of an encapsulated schwannoma with extensive myxomatous degeneration and multiple vessel thrombosis. The clinical, radiological, and histological features and the diagnostic approach of this rare entity are described.     

Schwannoma of the obturator nerve with urologic manifestations: report of a case

Peripheral nerve tumors, which are called schwannomas because they arise from nerve sheath Schwann cells, are rare tumors than can develop at any site in the body but involve the limbs in over 50% of cases. Only 13% of schwannomas arise in the trunk; about 3% of schwannomas are retroperitoneal, and about 4% of retroperitoneal tumors are schwannomas. Pelvic schwannomas are equally uncommon and can develop in a broad range of structures. The most common presenting manifestation is a very large space-occupying lesion responsible for compression of neighboring organs. Excision of the tumor is often extremely difficult or impossible. Although obturator nerve schwannomas are exceedingly rare, their paravesical location is suggestive of he diagnosis. Computed tomography and magnetic resonance imaging are the most useful investigations, although they cannot determine the exact nature of the tumor. During surgery, every effort should be made to preserve the integrity of the nerve, although this is not always possible; obturator nerve injury does not seem associated with severe impairments.     

Dorsal location of the cochlear nerve on vestibular schwannoma: preoperative evaluation, frequency, and functional outcome

The cochlear nerve is most commonly located on the caudoventral portion of the capsule of vestibular schwannomas and rarely on the dorsal portion. In such a condition, total removal of the tumor without cochlear nerve dysfunction is extremely difficult. The purpose of our study was to identify the frequency of this anatomical condition and the status of postoperative cochlear nerve function; we also discuss the preoperative radiological findings. The study involved 114 patients with unilateral vestibular schwannomas operated on via a retrosigmoid (lateral suboccipital) approach. Locations of the cochlear nerve on the tumor capsule were ventral, dorsal, caudal, and rostral. Ventral and dorsal locations were further subdivided into rostral, middle, and caudal third of the tumor capsule. The postoperative cochlear nerve function and preoperative magnetic resonance (MR) findings were reviewed retrospectively. In 56 patients that had useful preoperative hearing, useful hearing was retained in 50.0 % (28 of 56) of patients after surgery. The cochlear nerve was located on the dorsal portion of the tumor capsule in four patients (3.5 %), and useful hearing was preserved in only one of these patients (25 %) in whom the tumor had been partially resected. This tumor-nerve anatomical relationship was identified in all tumors of <2 cm at preoperative MR cisternography. MR cisternography has the potential to identify the tumor–nerve anatomical relationship, especially in small-sized tumors that usually require therapeutic intervention that ensures hearing preservation. Hence, careful evaluation of the preoperative MR cisternography is important in deciding the therapeutic indications.     

Schwannoma of the intermediate nerve

The intermediate nerve is seldom identified as the site of tumor origin in cerebellopontine angle schwannomas. A 29-year-old man presented with a 6-month history of slowly progressive hearing loss and dizziness; facial nerve weakness was not observed clinically. Magnetic resonance imaging revealed a tumor in the left cerebellopontine angle region extending up to the geniculate ganglion and along the course of the superficial petrosal nerve. A CT scan showed enlargement of the facial nerve canal. Microsurgery was performed via an extended retrosigmoid approach. Intraoperative and electrophysiological findings identified the intermediate nerve as the site of tumor origin.     

异位支配对正中神经尺神经损伤诊断影响的研究

目的 了解正中神经和尺神经之间交通支的存在对前臂这两条神经损伤诊断的影响,前臂正中神经至尺神经的交通支(Martin-Gruber anastomosis,MGA)、前臂尺神经至正中神经的交通支(reversed Martin-Gruber anastomosis,RMGA)和手部尺神经至正中神经的交通支(Riche-Cannieu anastomosis,RCA).方法 将160例正中神经或尺神经损伤合并存在异常交通支的患者分为三组:尺神经损伤并MGA组65例;正中神经损伤并RMGA组8例;正中神经损伤并RCA组87例.就其解剖基础、临床表现、电生理表现以及诊断进行讨论.结果 正中神经或尺神经损伤时,受损神经所支配肌肉的功能由于异常交通支的存在而得以代偿,导致其临床表现与神经损伤情况及其电生理表现不符.结论 充分了解正中神经和尺神经之间三种异常交通支的特点,对正中神经或尺神经损伤的临床诊断和治疗有重要意义,同时也可以避免错误地解释相关神经电生理检测的结果.     

Surgical approaches and complications in the removal of vestibular schwannomas. 2007

Vestibular schwannomas are benign tumors that usually originate from the balance portion of cranial nerve VIII. The treatment options currently available for vestibular schwannomas include observation with serial imaging, stereotactic radiation, and microsurgical removal. Although the ultimate goal in treatment of vestibular schwannomas is preservation of life, the best option for each patient depends on symptoms, tumor size, tumor location, and the patient's general health and age. Surgical exposure of the cerebellopontine angle for removal of vestibular schwannomas can be performed safely via a translabyrinthine, retrosigmoid, and middle fossa approach. Each approach has its advantages and disadvantages. The goal of surgery is complete eradication of tumor with preservation of hearing and facial nerve function when possible.     

Facial nerve schwannomas

A study of 26 patients with facial nerve schwannomas treated at the University Hospital of Zurich was done. The general clinical features are described, but particular emphasis is placed on tumor histologic findings, recovery of facial function after grafting, and the nature of intracranial facial nerve schwannomas Presenting symptoms are stratified by tumor location, with facial dysfunction being commonest with intracranial tumors, neurotologic symptoms being associated with intracranial tumors, and parotid masses being a feature of extratemporal tumors. We found no differences in tumor histology regardless of site of origin. Clinical, histologic, and radiologic evidence is reviewed, and from this evidence we conclude that intracranial facial nerve schwannomas may be particularly invasive acoustic schwannomas. Recovery of facial movement after grafting the facial nerve is not influenced by graft length or graft type. Prolonged preoperative facial dysfunction has a negative influence on recovery after grafting.     

Giant vestibular schwannomas: focusing on the differences between the solid and the cystic variants

In vestibular schwannomas (VS), the tumour size, as well as the size of the cystic component, have a considerable bearing on the outcome. This study addresses the differences between the cystic and solid variants of giant vestibular schwannomas. The study included 62 patients with giant VSs, of which 40 were solid and 22 were cystic (those in which cystic component greater or equal to 30% of the total tumour volume). The cystic tumour group was further divided into type A (31-60% volume of the cyst within tumour), type B (61-90% intra-tumoural cyst volume) and type C (more than 90% volume of the cyst). The clinicoradiological features, operative findings, histopathological characteristics and outcome of surgery of the two groups were compared. The mean duration of symptoms for the solid and cystic tumours were 21.1 and 26.2 months, respectively. However, six patients with cystic tumours showed recent and rapid neurological deterioration after a protracted existence. Papilloedema, lower cranial nerve involvement, facial paraesthesias and preoperative hydrocephalus were significantly more in cystic tumours. Total excision was achieved in 38 of the solid and 18 of the cystic tumours. VIIth nerve preservation was higher in the cystic lesions [solid 33/40 (82.5%), cystic 21/22 (95.4%)]. Myxoid degeneration, lobular growth patterns and cellular atypia were more prominent in the cystic variants. The giant vestibular schwannomas were associated with a higher incidence of cystic degeneration than has been reported for smaller tumours in literature. In cystic lesions, VIIth nerve preservation was higher due to early decompression of the lesion that facilitated in early identification of the VIIth nerve, except in patients with type C cystic tumour.     

Facial Nerve Schwannomas

A study of 26 patients with facial nerve schwannomas treated at the University Hospital of Zurich was done. The general clinical features are described, but particular emphasis is placed on tumor histologic findings, recovery of facial function after grafting, and the nature of intracranial facial nerve schwannomas Presenting symptoms are stratified by tumor location, with facial dysfunction being commonest with intracranial tumors, neurotologic symptoms being associated with intracranial tumors, and parotid masses being a feature of extratemporal tumors. We found no differences in tumor histology regardless of site of origin. Clinical, histologic, and radiologic evidence is reviewed, and from this evidence we conclude that intracranial facial nerve schwannomas may be particularly invasive acoustic schwannomas. Recovery of facial movement after grafting the facial nerve is not influenced by graft length or graft type. Prolonged preoperative facial dysfunction has a negative influence on recovery after grafting.     

Are Facial Nerve Outcomes Worse Following Surgery for Cystic Vestibular Schwannoma?

Objectives: This study sought to determine explicitly whether postsurgical facial nerve outcomes for patients with a cystic component to a vestibular schwannoma were significantly different from those with a solid tumor. Design: Seventy patients who underwent translabyrinthine surgery for a cystic vestibular schwannoma between May 1981 and the present, and who had complete records in our database, were identified. These were compared with a group of patients with solid tumors matched to the study group on the following parameters: House-Brackmann grade at presentation, tumor size, surgical approach, age. Setting: Regional tertiary referral center. Participants: Adult patients with vestibular schwannomas. Main Outcome Measures: House-Brackmann score 2 years following surgery. Results: No significant difference was found between the two groups. Conclusions: The perceived difference in outcomes between cystic and solid vestibular schwannomas cannot be demonstrated when confounding factors such as tumor size are taken into account.     

Recognizing schwannomatosis and distinguishing it from neurofibromatosis type 1 or 2

BACKGROUND DATA: Schwannomatosis has become a newly recognized classification of neurofibromatosis. Although the genetic loci are on chromosome 22, it lacks the classic bilateral vestibular schwannomas as seen in NF-2. We present the surgical treatment of 4 patients with schwannomatosis, including a brother and sister. METHOD: Case 1 presented with multiple progressively enlarging peripheral nerve sheath tumors. Case 4 presented with a trigeminal schwannoma and a vagal nerve schwannoma. Three of 4 patients had spinal intradural, extramedullary nerve sheath tumors. Surgery in all was multistaged and consisted of spinal laminectomies, site-specific explorations, and microsurgical tumor dissection and resection, with intraoperative neurophysiologic monitoring (including somatosensory-evoked and motor-evoked potentials, upper extremity electromyography and intraoperative nerve action potential monitoring, as appropriate). RESULTS: Intraoperatively the schwannomas had cystic and solid features and in all surgical cases the tumors arose from discrete fascicles of sensory nerve roots or sensory peripheral nerve branches. None of the patients experienced neurologic worsening as a result of their resections. Pathologic analysis of specimens from all cases demonstrated schwannoma. CONCLUSIONS: Not all patients with multiple schwannomas of cranial nerve, spinal nerve root, or peripheral nerve origin have NF-1 or NF-2. In schwannomatosis, these lesions are present in the absence of cutaneous stigmata, neurofibromas, vestibular schwannomas, or parenchymal brain tumors. Schwannomas in schwannomatosis can be large, cystic, and multiple. However, the predominant nerve involvement seems to be sensory and discrete fascicular in origin, facilitating microsurgical resection with minimal deficit.     

Paraspinal plexiform schwannoma of unknown nerve origin: A case report

Introduction and importanceSchwannomas are benign, slow-growing nerve sheath tumors of neoplastic Schwann cells. They are the most common peripheral nerve tumors in adults and are typically discovered incidentally due to their asymptomatic presentation. Despite the fact that most schwannomas are unassociated with a syndrome, their etiology is thought to be related to alterations or loss of the neurofibromatosis type two tumor suppressor gene.Case presentationWe present the case of a fifteen-year-old female who presented with a recurrent lower back/upper buttocks 9 cm mass with imaging suspicious for schwannoma. Needle biopsy revealed an S100 positive cellular schwannoma with patchy Ki-67. During surgical dissection down to the sacrum, no nerve of origin was identified.Clinical discussionSchwannomas have no pathognomonic findings on MRI and may occur at any location that Schwann cells are present; therefore, confirming a diagnosis relies on histopathology. Plexiform schwannomas are defined by a “network-like” intraneural growth pattern and are exceedingly rare in paediatric populations. A location distinct from the spinal canal is also very rare as schwannomas typically originate from the head and neck region.ConclusionPaediatric plexiform schwannomas have been rarely reported. Surgical planning relies on multiple factors such as tumor size, tumor location, pathologic features and symptomatic burden. The distinctive features of this case including an unknown nerve origin and a location outside the spinal canal provide a unique opportunity to discuss the diagnosis and management of paraspinal schwannomas and the impact on operative planning when a nerve of origin is not identified.     

Expanding the spectrum of malignant change in schwannomas: epithelioid malignant change, epithelioid malignant peripheral nerve sheath tumor, and epithelioid angiosarcoma: a study of 17 cases

Schwannomas (neurilemmomas) rarely undergo malignant change, most often in the form of either malignant peripheral nerve sheath tumor (MPNST) or angiosarcoma. We characterize the clinical features and the histopathologic spectrum of 17 schwannomas with evidence of malignant change. The study group comprised 7 males and 10 females with an age range of 16 to 76 years, (median, 40 yrs). None of the patients had neurofibromatosis. Lesions ranged in size from 0.6 to 10.5 cm (median, 4.0 cm) and arose mainly in the limbs/limb girdles (7 cases) or head and neck region (7 cases). All tumors contained areas of conventional benign schwannoma. Four cases of pure epithelioid malignant peripheral nerve sheath tumor (EMPNST) were identified, three of which showed immunopositivity for S-100 protein. Four angiosarcomas were identified, predominantly epithelioid-type. Ten schwannomas had an appearance that we have designated epithelioid malignant change (EMC) and, in one of these, EMC coexisted with EMPNST. Large epithelioid cells with abundant eosinophilic cytoplasm, vesicular chromatin, and prominent nucleoli (morphologically similar to cells of EMPNST) were distributed throughout the schwannoma--singly, in clusters, and in one case a microscopic nodule of such cells was also present. These large epithelioid cells were strongly positive for S-100 protein. Although follow-up data so far are limited, 1 of 5 patients with EMC in whom meaningful follow up was available developed repeated local recurrence (median follow up, 21 mos), one patient each with EMPNST and angiosarcoma died of local and metastatic disease. Pure EMPNST is rare; however, we confirm the tendency of MPNST to show epithelioid cytomorphology when arising in a benign schwannoma. We also confirm the distinctive (albeit infrequent) tendency of angiosarcoma to arise in schwannomas. We describe EMC in schwannomas and suggest that this represents a putative precursor lesion of EMPNST. At this time, we do not have an explanation for the tendency of schwannomas to show epithelioid cytomorphology when they undergo malignant change.     

Median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery

Median nerve compression in the carpal tunnel by a thrombosed persistent median artery and a large aberrant artery substituting for the radial artery has been described but there have been no reports of median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery. A 46 year old man is described who presented with clinical and electrophysiological features consistent with a median neuropathy at the wrist but surgical exploration revealed median nerve compression in the palm of the hand by an anomalously enlarged palmar branch of the ulnar artery. This case highlights another treatable cause of median nerve compression and illustrates that symptoms suggestive of carpal tunnel syndrome may be produced by median nerve compression in the palm of the hand.     

Successful resection of schwannoma from an intercostal nerve causing bloody pleural effusion: Report of a case

We report a case of schwannoma arising from the 9th intercostal nerve, which caused a bloodstained pleural effusion. The patient, a 37-year-old woman, presented with left-sided back pain. A chest X-ray showed left pleural effusion, which was subsequently found to be bloodstained but without malignant cells. Chest magnetic resonance imaging showed a 76-mm tumor arising from the 9th intercostal nerve. The tumor and intercostal nerve were successfully resected. Histological examination revealed that the tumor comprised spindle cells with both Antoni types A and B patterns. There were necrotic changes and cystic degeneration, but no atypical or mitotic cells. Based on these findings, benign schwannoma was diagnosed. Schwannoma is rarely accompanied by bloody pleural effusion, which we assume was caused by partial tumor rupture. Magnetic resonance imaging proved very useful in localizing and characterizing the tumor in this case.     

Intracerebral schwannoma: case report

BACKGROUND AND PURPOSE: We report a well-documented case of intracerebral schwannoma, presenting as a cystic and solid parietal mass, arising in a 20-year-old woman. Possible mechanisms underlying the histogenesis of this rare lesion are discussed. METHODS: The clinical, radiological and pathological features are described. The relevant literature is reviewed. RESULTS: The patient presented seizures and elevated intracranial pressure. Neuroradiologic findings showed a right parietal lesion with cystic and tissular components, intensely enhanced after injecting intravenous gadolinium. The tumor was removed through a right parietal craniotomy. Histological and immunochemical features confirmed the diagnostic of intracerebral schwannoma. The patient is alive without progressive local disease or metastasis. The origin of intracerebral schwannomas has been the source of much controversy. The most popular hypothesis argues that these tumors arise from the proliferation of Schwann cells in the perivascular nerve plexii. CONCLUSIONS: Intracerebral schwannoma is an extremely rare benign tumor. About fifty cases have been reported. The importance of recognizing this tumor is stressed, particularly in younger patients, given its benign nature, radiological resemblance to other tumors and favorable response to resection without toxic treatment.     

Hamartomas of the internal auditory canal: report of two cases

OBJECTIVE AND IMPORTANCE: To highlight the clinical, radiological, and surgical findings and therapeutic options for this rare entity, which may mimic a purely intrameatal vestibular schwannoma, and to define the particular aspects of preoperative differential diagnosis and surgical management. CLINICAL PRESENTATION: Two patients presented with clinical findings typical of vestibular schwannomas, i.e., tinnitus, hearing loss of 30 dB, and an intrameatal contrast-enhancing lesion on magnetic resonance imaging studies. TECHNIQUE: The lesions were exposed via a suboccipital transmeatal approach, and tumor infiltration of the cochlear and/or facial cranial nerves was identified. In view of the unclear intraoperative histology, surgical management was based on criteria of cranial nerve function. In Patient 1, after nerve decompression by subtotal tumor removal, preserved auditory brainstem responses and facial nerve electromyography indicated functional nerve preservation and facilitated the decision for partial resection. In Patient 2, minimal tumor dissection resulted in complete loss of auditory brainstem response without reversibility. Therefore, a radical tumor removal was performed that sacrificed the cochlear but preserved the facial nerve. CONCLUSION: Symptoms and signs of internal auditory canal hamartomas are congruent with other typical pathological lesions of the internal auditory canal and cerebellopontine angle. Accurate preoperative diagnosis by radiological means is not possible, but careful evaluation of the different signal intensities on magnetic resonance imaging studies may indicate this rare pathological condition. Intraoperative surgical findings of tumor infiltration of the faciocochlear cranial nerve complex may support simple observation. In view of the nonneoplastic characteristic of these lesions, a more conservative approach is justified. The decision should be based on the functional status of the cranial nerves, for which reliable electrophysiological monitoring is indispensable.