Meningiomas, Epidermoids, And Other Nonacoustic Tumors Of The Cerebellopontine Angle

Characterization of facial nerve outcomes following radiosurgery for vestibular schwannoma: a meta-analysis

PURPOSE

Gamma Knife radiosurgery (GKRS) is a precise and efficacious treatment modality for vestibular schwannoma (VS) with favorable cranial nerve preservation rates. This study aims to better characterize facial nerve (FN) outcomes in VS after GKRS.

METHODS

A query of six medical databases was conducted following PRISMA guidelines. Eligible studies exclusively reported VS managed with single-fraction GKRS and included House-Brackmann (HB) scale assessments prior to and following GKRS. Data was analyzed using random-effects modeling, and FN preservation was defined as HB I or II at last follow-up.

RESULTS

Data was analyzed from 15 articles with 3,155 patients at an mean age of 55.0 years. Mean tumor volume, radiation dose, follow-up, tumor control, and hearing preservation were 4.28 cm3, 13.3 Gy, 59.4 months, 92.7%, and 62.6%, respectively. The pooled FN preservation rate was 92.9%. Mean preoperative tumor volume > 2.5 cm3 and age > 60 years were significantly associated with worse preoperative FN function (p = 0.019, p = 0.023, respectively). Normal FN function (HB = 1) at last follow up was 95.8% for VS volume < 2.5 cm3 and 89.4% with larger volumes (p < 0.001). Doses ≤ 13 Gy were significantly associated with superior FN preservation (96.5%) compared to higher doses (p < 0.001). Tumor control and hearing preservation were not significantly associated with FN preservation.

CONCLUSION

This meta-analysis identifies tumor volume and radiation dose as prognostic factors for FN preservation. A FN preservation rate of 93% may be expected at five years after GKRS. This study provides a unique characterization of FN outcome that should be considered in the management of VS.

Primary glioblastoma of cerebellopontine angle: The diagnostic dilemma of this rare case

Supratentorial glioblastoma is a common primary intracranial tumor in adults. High-grade glioma in cerebellopontine angle (CPA) is rare. We describe a case of adult-type diffuse high-grade glioma of CPA in a 49-year-old female that was managed surgically at our institute. Glioblastoma is an infiltrating type of glioma (WHO grade 4). MRI helped in characterizing the lesion; however, diagnosis was confirmed on histopathology. This report aims at the imaging pattern of primary adult-type diffuse high-grade glioma (WHO grade 4) at cerebellopontine angle.

Is Preoperative Facial Palsy a Deterrent to Facial Nerve Preservation after Gross-Total Removal of Giant Vestibular Schwannomas?

Background Although rare in small vestibular schwannomas, preoperative facial nerve paresis is often present in giant schwannomas. Preserving facial nerve function in these cases remains a herculean task. This study evaluates the facial functions after complete tumor removal and whether preoperative facial nerve involvement affects postoperative functional status.

Methods This retrospective study from January 2014 to August 2021 excluded nongiant tumors (< 4 cm), neurofibromatosis type 2 cases, incomplete removals, redo surgeries, deaths, and cases done without nerve monitoring. These were grouped into preoperative facial palsy present (PFP) and no preoperative facial palsy (NFP). Facial nerve functions were assessed on first postoperative day, at the time of discharge, and at last follow-up and dichotomized into two groups: nondisfiguring (House–Brackmann [HB] grades I–III) and disfiguring (HB grades IV–VI). The cohort outcomes of patients with nondisfiguring PFP (HB grades I–III) were also analyzed.

Results There were 88 cases (PFP, n = 57; NFP, n = 31). Facial nerve was preserved anatomically in 62 (70.45%) patients (PFP, n = 38; NFP, n = 24) without any statistical difference (p = 0.29). Statistically significant disfiguring facial outcomes (HB IV, V, VI) were seen in patients with preoperative facial palsy (p = 0.01); however, a comparison of facial functions in patients with only nondisfiguring PFP with those in NFP group did not show the statistical difference (p = 0.12).

Conclusions Facial nerve palsy present before surgery does not seem to be a deterrent to intraoperative preservation of facial nerve during complete removal of giant vestibular schwannomas. Patients with nondisfiguring facial palsies have postoperative facial functions comparable to those without facial palsy.

Contralateral metastatic cerebellopontine angle glioblastoma: A rare manifestation

Background:

Glioblastoma is the most common glioma presenting within adults with an incidence of 10 per 100,000 people globally. These are mostly supratentorial tumors with rare cases of extra-axial spread. Even rarer is the presentation of glioblastoma within the cerebellopontine angle (CPA). Here, we present a case of a previously resected and irradiated glioblastoma metastasizing from the right temporal lobe region to the contralateral CPA.

Case Description:

A 24-year-old female who previously underwent surgery and concurrent chemoradiotherapy for a right temporal glioblastoma in August 2020, presented to us 6 months later with headaches, vomiting, and dizziness for the past 6 days. She had left-sided dysmetria on examination. MRI of the brain showed an extra-axial, heterogeneously enhancing lesion within the left CPA. The patient subsequently underwent a left retrosigmoid craniotomy and maximum safe resection of the lesion. Histopathology reported the lesion as a glioblastoma.

Conclusion:

Glioblastoma within the CPA is rarely reported within the literature. To date, our case is the first instance of an extra-axial contralateral metastasis of glioblastoma.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

Gender is associated with long-term mortality after cerebellopontine angle tumor resection

OBJECTIVE

Gender can contribute to adverse patient outcomes through social and biological factors. It is important to assess the effects of gender on long-term patient outcomes after care has already been accessed, in order to improve quality of care and mitigate healthcare disparities.

PATIENTS AND METHODS

277 consecutive patients undergoing cerebellopontine angle tumor resection over a six-year period (June 09, 2013 - April 29, 2019) at a university health system were retrospectively evaluated. Outcomes included 90-day emergency department (ED) visit, readmission, reoperation and mortality following resection. Male and female patients in the whole population were analyzed by logistic regression. Thereafter, Coarsened Exact Matching was used to match female and male on important demographic factors, including history of prior surgery, median household income, and Charlson Comorbidity Index (CCI) score, among others. Regression was carried out in the matched population, with significance set at a p-value < 0.05.

RESULTS

In the matched population analysis, males were significantly more likely to experience mortality during the length of follow-up (p = 0.03) but not within 90-days of resection. There were no significant differences in 90-day mortality or reoperation during the length of follow-up in either the matched or pre-matched populations. No significant differences were found in any of the 90-day morbidity outcomes in either the matched or pre-matched populations.

CONCLUSION

Gender may predict long-term outcomes in patients following CPA tumor resection. It is possible that gender also contributes to outcome disparities in other neurosurgical procedures, which future studies should evaluate.

Reliability of clinical diagnosis of masses of the cerebellopontine angle: A retrospective multi-institutional study

OBJECTIVES

To assess the accuracy of pre-operative diagnosis of masses of the cerebellopontine angle (CPA) when compared to surgical pathology.

DESIGN

Retrospective chart review.

PARTICIPANTS

Patients who underwent surgery for CPA masses at two tertiary care institutions from 2007 to 2017.

MAIN OUTCOME MEASURES

Percent concordance between pre-operative and surgical pathologic diagnosis; sensitivity, specificity, positive predictive value, and negative predictive value for predicted diagnoses.

RESULTS

Concordance between pre-operative diagnosis and surgical pathology was 93.2% in 411 sampled patients. Concordance was 57.9% for masses other than vestibular schwannoma. Prediction of vestibular schwannoma and meningioma had high positive (0.95 and 0.97, respectively) and negative (0.76 and 0.99, respectively) predictive values. Prediction of facial neuroma had sensitivity of 0.13 and positive predictive value of 0.25. Headache (p = 0.001) and facial weakness (p = 0.003) were significantly associated with different pathologic profiles. Hearing loss was associated with differences in diagnostic prediction (p = 0.02) but not with differences in surgical pathology (p > 0.05).

CONCLUSIONS

Comparison between pre-operative predicted diagnosis and surgical pathology for cerebellopontine angle masses is presented. Vestibular schwannoma and meningioma were effectively identified while rarer CPA masses including facial neuroma were rarely identified correctly. Clinicians caring for patients with CPA masses should be mindful of diagnostic uncertainty which may lead to changes in treatment plan or prognosis.

Ectopic brain tissue in the trigeminal nerve presenting as rapid-onset trigeminal neuralgia: case report

The authors report the case of a 52-year-old man who presented with rapid-onset lancinating facial pain consistent with trigeminal neuralgia. Magnetic resonance imaging revealed a nonenhancing small lesion on the right trigeminal nerve concerning for an atypical schwannoma or neuroma. The patient underwent resection of the mass via a right retrosigmoid approach. His facial pain completely resolved immediately postoperatively and had not recurred at 6 months after surgery. The mass was consistent with normal brain tissue (neurons and glial cells) without evidence of mitoses. A final histopathological diagnosis of ectopic brain tissue with neural tissue demonstrating focal, chronic T-cell inflammation was made. The partial rhizotomy during resection was curative for the facial pain. To the authors' knowledge, this is the first report of neuroglial ectopia causing trigeminal neuralgia.

Spinal Myxopapillary Ependymoma Metastatic to Bilateral Internal Auditory Canals

Objectives

We report a rare case of spinal myxopapillary ependymoma metastatic to both internal auditory canals (IACs) and its implications for diagnosing neurofibromatosis type 2 (NF2).

Methods

We present a detailed clinical history, magnetic resonance imaging (MRI), intraoperative photographs, and histopathologic findings from a patient with bilateral IAC lesions, and review the diagnostic criteria for NF2.

Results

An 11-year-old boy with surgically resected spinal myxopapillary ependymoma, treated with total spine irradiation for recurrence, later showed bilaterally enhancing IAC lesions on T1-weighted MRI with contrast. The diagnosis of NF2 with bilateral vestibular schwannomas was entertained. Close examination of T2-weighted MRI, however, demonstrated the masses to be isointense to cerebrospinal fluid. This finding raised the possibility of other, more unusual IAC lesions. The patient underwent sequential suboccipital craniotomies for tissue diagnosis, and both IAC lesions were found to be myxopapillary ependymomas.

Conclusions

This is the youngest reported patient with metastatic myxopapillary ependymoma. Although vestibular schwannomas account for the majority of contrast-enhancing T1-weighted IAC lesions, other uncommon lesions may present in a similar manner. A T2 fast-spin echo screening MRI would have missed this patient's lesions. Therefore, both T1-weighted MRI with or without contrast and T2-weighted MRI may be necessary to distinguish vestibular schwannoma from other, more unusual IAC lesions.

Morphometry and microsurgical anatomy of Bochdalek's flower basket and the related structures of the cerebellopontine angle

BACKGROUND

Bochdalek's flower basket (Bfb) is the distal part of the horizontal segment of the fourth ventricle's choroid plexus protruding through the lateral aperture (foramen of Luschka). The microsurgical anatomy of the cerebellopontine angle, fourth ventricle and its inner choroid plexus is well described in the literature, but only one radiological study has investigated the Bfb so far. The goal of the present study was to give an extensive morphometric analysis of the Bfb for the first time and discuss the surgically relevant anatomical aspects.

METHOD

Forty-two formalin-fixed human brains (84 cerebellopontine angles) were involved in this study. Photomicrographs with scale bars were taken in every step of dissection to perform further measurements with Fiji software. The lengths and widths of the Bfb, rhomboid lip and lateral aperture of the fourth ventricle as well as the related neurovascular and arachnoid structures were measured. The areas of two sides were compared with paired t-tests using R software. Significance level was set at p < 0.05.

RESULTS

Protruding choroid plexus was present in 77 cases (91.66%). In 6 cases (7.14%), the Bfb was totally covered by the rhomboid lip, and in one case (1.19%), it was absent. The mean width of the Bfb was 6.618 mm (2-14 mm), the mean height 5.658 mm (1.5-14 mm) and mean area 25.80 mm² (3.07-109.83 mm²). There was no statistically significant difference between the two sides (p = 0.1744). The Bfb was in contact with 20 AICAs (23.80%), 6 PICAs (7.14%) and 39 vestibulocochlear nerves (46.42%). Arachnoid trabecules, connecting the lower cranial nerves to the Bfb or rhomboid lip, were found in 57 cases (67.85%).

CONCLUSIONS

The Bfb is an important landmark during various surgical procedures. Detailed morphology, dimensions and relations to the surrounding neurovascular structures are described in this study. These data are essential for surgeons operating in this region.

CT- and MRI-based gross target volume comparison in vestibular schwannomas

AIM

This study represents an enumeration and comparison of gross target volumes (GTV) as delineated independently on contrast-enhanced computed tomography (CT) and T1 and T2 weighted magnetic resonance imaging (MRI) in vestibular schwannomas (VS).

BACKGROUND

Multiple imaging in radiotherapy improves target localization.

METHODS AND MATERIALS

42 patients of VS were considered for this prospective study with one patient showing bilateral tumor. The GTV was delineated separately on CT and MRI. Difference in volumes were estimated individually for all the 43 lesions and similarity was studied between CT and T1 and T2 weighted MRI.

RESULTS

The male to female ratio for VS was found to be 1:1.3. The tumor was right sided in 34.9% and left sided in 65.1%. Tumor volumes (TV) on CT image sets were ranging from 0.251 cc to 27.27 cc. The TV for CT, MRI T1 and T2 weighted were 5.15 ± 5.2 cc, 5.8 ± 6.23 cc, and 5.9 ± 6.13 cc, respectively. Compared to MRI, CT underestimated the volumes. The mean dice coefficient between CT versus T1 and CT versus T2 was estimated to be 68.85 ± 18.3 and 66.68 ± 20.3, respectively. The percentage of volume difference between CT and MRI (%VD: mean ± SD for T1; 28.84 ± 15.0, T2; 35.74 ± 16.3) and volume error (%VE: T1; 18.77 ± 10.1, T2; 23.17 ± 13.93) were found to be significant, taking the CT volumes as the baseline.

CONCLUSIONS

MRI with multiple sequences should be incorporated for tumor volume delineation and they provide a clear boundary between the tumor and normal tissue with critical structures nearby.

Metastases in cerebellopontine angle from the tumors of central nerve system

The objective of this study was to analyze the characters of the cerebellopontine angle (CPA) metastases from central nerve system (CNS) tumors. Ten patients were reviewed for the period between 2008 and 2015. The clinical and neuroimaging features, and treatment outcomes were analyzed retrospectively. The average period during primary diagnosis through the diagnosis of CPA metastases was 42.4months. Among the 10 cases, the primary tumors and metastases were found simultaneously in 3 cases, the metastases after primary tumor removal were found in 5 cases, and the metastases after stereotaxic radiosurgery were found in 2 cases. Only 4 patients presented with the symptoms and signs associated with CPA involving, one with hearing loss, one presenting facial paralysis, one suffering from tinnitus and one case with dizziness. There were 2 cases with the miliary metastases and 8 cases with massive metastases. There existed 3 cases with single CPA metastases, whereas 7 cases with multiple metastatic foci. Among the 8 cases of massive metastatic foci, 6 tumors presented the solid features and the other 2 cases exhibited cystic and solid features. In this cohort of cases, 4 cases were involved in the bilateral and 6 cases presented unilateral metastatic foci. The three CPA metastases were removed in this group, 6 case performed with radiotherapy, and 5 cases received chemotherapy. In the current group 5 patients have been dead, 3 patients kept stable and 2 cases experienced improvement. In spite of seldom previous reports regarding the metastases from CNS tumors occurring in the CPA are existent, this rare form of the disease should be considered in future evaluation as a differential diagnosis.

Evaluating the utility of a scoring system for lipomas of the cerebellopontine angle

BACKGROUND

Cerebellopontine angle (CPA) lipomas are rare, benign, slow-growing masses. Resections are considered in symptomatic patients who are refractory to targeted medical therapies, but at those stages the lipomas have often reached considerable sizes and encompass critical neurovascular structures. The objective of this study is to develop and to evaluate the utility of a scoring system for CPA lipomas. The hypothesis is that CPA lipomas with lower scores are probably best managed with early surgery.

METHODS

The PubMed database was searched using relevant terms. Data on patient and lipoma characteristics were extracted and used to design a scoring system. CPA lipomas were stratified by scores with corresponding managements and outcomes analyzed.

RESULTS

One hundred and seventeen patients with CPA lipomas were identified and 40 CPA lipomas were scored. The remaining CPA lipomas were deficient in data and not scored. No lipomas were scored as 1. Score 2 lipomas (n = 12; 30%) most often underwent serial surveillances (n = 5; 41.6%), with the majority of symptoms remaining unimproved (n = 2; 40%). Patients with score 2 CPA lipomas treated with medical therapies (n = 3; 25%) often experienced symptom resolution (n = 2; 66.6%) (p = 0.0499). Patients with score 2 CPA lipomas undergoing surgical resections (n = 3; 25%) all experienced symptom resolution (n = 3; 100%) (p = 0.0499). Score 3 was most common (n = 16; 40%) and these lipomas were often surgically resected (n = 10; 62.5%). The majority of patients with score 3 CPA lipomas having undergone surgical resections (n = 10; 62.5%) experienced symptom improvement (n = 1; 10%) or resolution (n = 4; 40%).

CONCLUSIONS

Score 2 CPA lipomas are smaller and would be deemed non-surgical in general practice. However, our data suggest that these lipomas may benefit from either medical therapies or early surgical resections. The advantages of early surgery are maximal resection, decreased surgical morbidity, and improved symptom relief.

Combined Transtemporal Access for Large (>3 cm) Meningiomas of the Cerebellopontine Angle

OBJECTIVES: Large meningiomas of the cerebellopontine angle present a formidable surgical challenge due to tumor vascularity, neural attachment, and brain stem compression. The purpose of this paper is to present our use of the combined transtemporal approach in the surgical treatment of 29 large meningiomas.

STUDY DESIGN AND SETTING: Twenty-nine patients with large meningiomas of the CPA were surgically treated through a combined retrosigmoid-transpetrosal-transcochlear approach at our tertiary care academic medical center from July 1995 through July 2004. Data was collected from a retrospective medical records review.

RESULTS: Total tumor removal was achieved in 19 of 29 (67%) of the patients and the facial nerve was anatomically preserved in 26 of 29 (89%) of the cases. Cerebrospinal fluid leakage was seen in 3.5% of the patients and additional transient cranial nerve deficits were noted in 14% of the cases, but no significant neurologic sequelae occurred. Of the 10 patients with residual tumor, 6 have been stable without growth, 2 were treated with reoperation for regrowth of disease, and 2 were controlled with localized radiotherapy.

CONCLUSIONS: This combined lateral transtemporal approach provided wide exposure to the cerebellopontine angle and optimized the surgical extirpation of 29 large meningiomas presented in this series.

Management of symptomatic hemifacial spasm or trigeminal neuralgia

Hemifacial spasm (HFS) or trigeminal neuralgia (TN) is a kind of hyperactivity disorder of cranial nerves caused by vascular compression. However, sometimes, the disease may arise from nerve damage produced by tumors, which was called as symptomatic HFS/TN. Until now, little is known about the exact mechanism and the necessity of microvascular decompression (MVD) regarding the tumor-induced HFS/TN, which is necessary to be retrospectively analyzed in a considerable sample. Among the 4021 patients who underwent MVD in our department between 2006 and 2014, 44 were finally diagnosed as symptomatic HFS or TN. These patients were focused in this study and their clinical features as well as intraoperative findings and postoperative outcomes were retrospectively investigated. Data analysis exhibited the symptomatic HFS/TN cases accounted for 1.1 % in the study, which were caused by epidermoid in 18 (40.9 %) and meningioma in 15 (34.1 %) followed by neuroma in 7 (15.9 %) as well as aneurysm in 2 (4.5 %) and arteriovenous malformation in 2 (4.5 %). Compared to those with idiopathic HFS/TN, younger females were more susceptible (p < 0.05). After resection of the neoplasm, the offending vessel was identified in 26 (59.1 %), which were followed by MVD process. Postoperatively, the symptoms relief rate was 88.6 %. Our study showed that surgical management of patients with symptomatic HFS/TN may lead to a satisfactory result, yet those primary lesions should be removed firstly. In some cases, a microvascular decompression process might be unnecessary afterward, but the entire nerve root should be checked to exclude any vessel in contact with.

Hearing disorders in brainstem lesions

Auditory processing can be disrupted by brainstem lesions. It is estimated that approximately 57% of brainstem lesions are associated with auditory disorders. However diseases of the brainstem usually involve many structures, producing a plethora of other neurologic deficits, often relegating "auditory symptoms in the background." Lesions below or within the cochlear nuclei result in ipsilateral auditory-processing abnormalities detected in routine testing; disorders rostral to the cochlear nuclei may result in bilateral abnormalities or may be silent. Lesions in the superior olivary complex and trapezoid body show a mixture of ipsilateral, contralateral, and bilateral abnormalities, whereas lesions of the lateral lemniscus, inferior colliculus, and medial geniculate body do not affect peripheral auditory processing and result in predominantly subtle contralateral abnormalities that may be missed by routine auditory testing. In these cases psychophysical methods developed for the evaluation of central auditory function should be employed (e.g., dichotic listening, interaural time perception, sound localization). The extensive connections of the auditory brainstem nuclei not only are responsible for binaural interaction but also assure redundancy in the system. This redundancy may explain why small brainstem lesions are sometimes clinically silent. Any disorder of the brainstem (e.g., neoplasms, vascular disorders, infections, trauma, demyelinating disorders, neurodegenerative diseases, malformations) that involves the auditory pathways and/or centers may produce hearing abnormalities.

Management of cerebellopontine angle lipomas: need for long-term radiologic surveillance?

OBJECTIVE

To date, only a very limited number of lipomas of the cerebellopontine angle (CPA) have been reported. Our objective was to examine clinical and radiologic features of CPA lipomas and determine the most appropriate management plan.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients with CPA lipomas were identified through the skull base multidisciplinary meeting database.

INTERVENTIONS

Radiologic surveillance and clinical assessment.

MAIN OUTCOME MEASURES

Tumor growth, assessed through radiologic measurements on serial magnetic resonance imaging, demographics, presenting symptoms, and any correlation between weight gain and lipoma growth were among the examined factors.

RESULTS

Of the 15 patients with CPA lipomas, six were female and nine were male, with an average age at presentation of 50.2 years (range, 31.7-76.4 yr) and an average follow-up time of 51.7 months (range, 6-216 mo). The lipomas were unilateral in all cases, nine on the right (60%) and six on the left (40%) side. None of the lipomas increased in size. All patients were treated conservatively. Sensorineural hearing loss was the main presenting symptom (80%) followed by tinnitus (46.7%) and vertigo (20%). None of the patients suffered from facial nerve dysfunction. There was no correlation between weight gain and tumor growth.

CONCLUSION

CPA lipomas can be diagnosed accurately with appropriate magnetic resonance imaging techniques and be managed conservatively with safety. Cochleovestibular are the most common presenting symptoms, whereas facial nerve involvement is rare. CPA lipomas do not tend to grow and can be monitored on a less regular basis.

Pediatric cerebellopontine angle and internal auditory canal tumors: clinical article

OBJECT

The aim in this study was to describe the clinical presentation, differential diagnosis, and risk for neurofibromatosis Type 2 (NF2) in pediatric patients presenting with cerebellopontine angle (CPA) and internal auditory canal (IAC) tumors.

METHODS

The authors conducted a retrospective study at a tertiary care academic referral center. All patients with an age ≤ 18 years who had presented with an extraaxial CPA or IAC tumor between 1987 and 2012 were included in the study cohort. Data regarding symptoms, diagnosis, tumor characteristics, and NF2 status were collected and analyzed.

RESULTS

Sixty patients (55% female, 45% male) harboring 87 tumors were identified. The mean age at diagnosis was 12.8 years (median 14.0 years, range 0.9-18.9 years). Schwannomas were the most commonly identified lesions (57 of 87 tumors, including 52 vestibular, 3 facial, and 2 trigeminal schwannomas), followed by meningiomas (5 of 87) and epidermoid cysts (4 of 87). Six malignant tumors were diagnosed, including small-cell sarcoma, squamous cell carcinoma, malignant meningioma, atypical rhabdoid-teratoid tumor, endolymphatic sac tumor, and malignant ganglioglioma. Headache, followed by hearing loss and imbalance, was the most common presenting symptom, whereas dysphagia, otalgia, and facial pain were uncommon. Neurofibromatosis Type 2 was diagnosed in 20 (61%) of 33 patients with vestibular schwannoma (VS), while the other 13 patients (39%) had sporadic tumors. Nineteen of the 20 patients with NF2 met the diagnostic criteria for that disorder on initial presentation, and 15 of them presented with bilateral VS. At the last follow-up, 19 of the 20 patients subsequently diagnosed with NF2 demonstrated bilateral VSs, whereas 1 patient with a unilateral VS and multiple other NF2-associated tumors has yet to demonstrate a contralateral VS to date. Only 1 patient presenting with an isolated unilateral VS and no family history of NF2 demonstrated a contralateral VS on subsequent radiological screening.

CONCLUSIONS

Cerebellopontine angle and IAC tumors in the pediatric population are rare. There are several noteworthy differences between the adult and pediatric populations harboring these lesions. While VS is the most common pathology in both age groups, the lesion was found in only 60% of the pediatric patients in the present study. Unlike in adults, VSs in the pediatric population were associated with NF2 in over one-half of all cases. The majority of pediatric patients with NF2 fulfilled the diagnostic criteria at initial presentation; however, approximately 7% of patients presenting with a seemingly sporadic (no family history of NF2) unilateral VS will meet the criteria for NF2 later in life. Finally, malignancies account for a significantly higher percentage (10%) of cases among pediatric patients. These findings underscore the importance of early screening and close radiological follow-up and may be helpful in patient counseling.

Lipochoristomas of the cerebellopontine angle and internal acoustic meatus: a seven-case review

BACKGROUND

Intracranial lipomas are extremely rare tumors, with certain clinical and radiological characteristics.

METHODS

We considered the diagnostic evaluation and treatment options of seven patients presenting with lipoma in the cerebellopontine angle or internal acoustic meatus in our department.

RESULTS

Mean age was 51, with four out of seven cases being women. Balance disorders (vertigo, dizziness) were the predominant symptoms (in six out of seven patients), followed by hearing loss. The diagnosis of intracranial lipomas was based on the results of imaging studies, especially on magnetic resonance imaging. The management of lipomas of the CPA and of the IAM should initially be conservative, including close follow-up of the patient and evaluation of a potential change in tumor size. Surgical management of CPA lipomas should be reserved for patients with intractable clinical symptoms due to tumor overgrowth.

CONCLUSIONS

Diagnosis of CPA and IAM lipomas is considered to be a clinical and imaging challenge. As the complete resection of such lipomas is a risky choice and taking into account the benign course of such tumors, the only absolute surgical indication should be uncontrolled tumor growth.

Risk factors and tumor response associated with hydrocephalus after gamma knife radiosurgery for vestibular schwannoma

BACKGROUND

This study was designed to investigate the clinical characteristics and risk factors of hydrocephalus after gamma knife radiosurgery (GKRS) for vestibular schwannoma.

METHODS

The authors retrospectively reviewed clinical and neuroimaging findings of 221 patients who underwent GKRS for newly diagnosed vestibular schwannoma. Mean patient age was 54.1 years (range 7-83 years), mean tumor volume was 3,010.4 mm(3) (range 34.7 to 14,300 mm(3)), mean marginal dose was 12.5 Gy (range 11 to 15 Gy), and mean follow-up duration was 31.9 months (range 1 to 107.6 months).

RESULTS

Surgical intervention for cerebrospinal fluid (CSF) diversion after GKRS was necessary in 11 (5 %) of the patients. Median time between GKRS and ventriculoperitoneal (VP) shunt placement was 15.5 months (range 1.8-37.8 months). These 11 patients showed female predominance (11 females) and mean tumor volume was significantly larger than in the other without hydrocephalus (6,509 vs. 2,726 mm(3); p < 0.01). Decreases in tumor enhancement and swelling were observed in all 221 patients, and CSF protein was found to be elevated in five of nine patients with available data at the time of the shunt procedure. Hydrocephalic symptoms improved after VP shunt and tumor sizes further decreased at last follow-up in all patients.

CONCLUSIONS

Hydrocephalus after radiosurgery may co-occur with a temporary change of tumor volume after radiation treatment. Therefore, hydrocephalus should be kept in mind during the time of tumor volume transition. Furthermore, the authors suggest that frequent patient monitoring for hydrocephalus be maintained for up to 3-4 years after GKRS.

Normal pressure hydrocephalus after gamma knife radiosurgery for cerebellopontine angle meningioma

There are no reports of hydrocephalus following radiosurgery for a meningioma. We report on a case where gamma knife therapy for a 4 cm diameter right cerebellopontine meningioma accelerated hydrocephalus three months post treatment. Examination of the cerebrospinal fluid (CSF) revealed a high protein level and thus, CSF malabsorption and CSF obstruction might have occurred after the radio surgery. It is important to consider this pathology, and the need for long term follow up.

Case report of glomus jugulare tumour associated with a posterior fossa cyst

A subgroup of complex glomus jugulare tumours exists. This includes: multiple, giant or neuropeptide-secreting lesions; those associated with other lesions, such as dural arterio-venous malformation or an adrenal tumour; and tumours in which there has been previous treatment with adverse outcome. To our knowledge, we present the first case of a glomus jugulare tumour associated with a posterior fossa cyst. This entity should be included in the subgroup of complex glomus jugulare tumours.

Endoscopic fenestration of middle fossa arachnoid cysts: a technical description and case series

BACKGROUND

Arachnoid cysts are intra-arachnoidal cerebrospinal fluid collections most frequently seen in the middle cranial fossa. The optimal method of treatment for symptomatic arachnoid cysts remains controversial and includes cyst shunting, open craniotomy and endoscopic fenestration. All these techniques, however, have been associated with the development of postoperative subdural fluid collections. We describe a new endoscopic transcortical technique that attempts to avoid this complication.

METHODS

Six patients with middle cranial fossa arachnoid cysts were treated with endoscopic fenestration at our institution between January 2002 and December 2005. Three cases were approached directly through the cyst, while the other 3 were approached by passing the endoscope through the rim of adjacent cortex.

RESULTS

All six endoscopic fenestrations were successful in treating the arachnoid cysts. Among the 3 patients treated via a direct cyst entry, 2 cases developed significant subdural hygromas, 1 of which required aspiration. On the other hand, 1 of the 3 cases treated using a transcortical technique developed an insignificant postoperative extra-axial collection that resolved at 3 months without intervention.

CONCLUSION

Endoscopic fenestration is an effective treatment for symptomatic arachnoid cysts. Endoscopic fenestration via a transcortical approach attempts to minimize cerebrospinal fluid drainage into the subdural space, avoiding the development of significant postoperative extra-axial collections, while promoting flow into the basal cisterns.

Lipoma of the cerebellopontine angle

Lipomas of the cerebellopontine angle (CPA) are unusual tumors that typically present with hearing loss, tinnitus, dizziness, and occasionally facial neuropathies. We describe the case of a healthy 42-year-old woman who presented with left-sided hearing loss and facial synkinesis. T1-weighted magnetic resonance imaging revealed an enhancing lesion of the left CPA with no signal on fat suppression sequences. Despite conservative therapy, the patient developed progressive hemifacial spasm, and a suboccipital craniotomy approach was used to debulk the tumor, which encased cranial nerves V, VII, VIII, IX, X, and XI. Surgical histopathology demonstrated mature adipocytes, consistent with lipoma. Two years after surgery, the patient remains free of facial nerve symptoms. Cerebellopontine angle lipomas are rare lesions of the skull base and are reliably diagnosed with T1-weighted and fat suppression magnetic resonance sequences, which we recommend in the routine radiologic workup of CPA tumors. Accurate preoperative diagnosis is crucial because most CPA lipomas should be managed conservatively. Partial surgical resection is indicated only to alleviate intractable cranial neuropathies or relieve brainstem compression.

Clinical presentation of posterior fossa epidermoid cysts

The aim of this study was to investigate the audiovestibular deficits in those with posterior fossa epidermoid cyst including cerebellopontine angle in two patients and cerebellum in one patient. Prior to operation, all three patients showed bilateral gaze nystagmus. Audiometry revealed mild hearing loss in two patients, and caloric test displayed canal paresis in two patients. After operation, subsidence of gaze nystagmus and recovery of caloric responses were disclosed in all patients. Two patients had both hearing and vestibular evoked myogenic potential (VEMP) results recovered to normal. In contrast, the only one who underwent craniotomy twice displayed bilateral mild hearing loss and delayed VEMPs, possibly due to operation sequela. Hence, bilateral gaze nystagmus may present as an initial sign for posterior fossa epidermoid cyst. Audiovestibular deficits in cases of epidermoid cyst are attributable to compression neuropathy, which may resolve and return to normal responses after surgery.

Rare tumors of the internal auditory canal

The study was performed to identify the incidence and histology of rare tumors with growth restricted to the internal auditory canal (IAC) that are different from vestibular schwannoma (VS). Furthermore, the question was addressed whether a preoperative diagnosis would be possible in these cases. A series of 351 patients that were operated on for IAC tumors through a transtemporal or translabyrinthine approach was investigated retrospectively. Cases with a tumor entity other than VS were analyzed for symptoms, radiological diagnosis, intraoperative findings and postoperative histolopatology to determine if a differential diagnosis to the common VS can be established prior to surgery. In 15 out of 351 cases (4.3%), uncommon processes of the IAC were determined by histology (6 lipomas, 3 hemangiomas, 2 neurofibromas, 2 menigiomas, 1 facial neuroma and 1 case of bilateral malignant lymphoma). The symptoms and the clinical manifestations were typical for patients with VS so that a preoperative differential diagnosis was not possible in the majority of cases. An analysis of the operation reports revealed that in 10 out of the 15 cases the surgeon suspected an unusual tumor of the IAC during surgery. The results of the present investigation suggest that rare lesions of the IAC can be expected in less than 5% of the cases and that preoperative diagnosis of rare IAC tumors is difficult. Intraoperative findings such as adhesion to cranial nerves and consistency of the tumor often indicate unusual processes, but histological analysis of the removed tissue is essential for the definite diagnosis.

Meningiomas of the cerebellopontine angle with extension into the internal auditory canal

OBJECT

Only some meningiomas of the cerebellopontine angle (CPA) extend into the internal auditory canal (IAC) or arise from its dural lining. The authors investigated cases of CPA tumors in which the meningioma was inserted in the dura mater in or at the ICA or infiltrated a cranial nerve.

METHODS

The authors reviewed patient charts including surgical and clinical records, intraoperative recordings of auditory evoked potentials, records of postoperative auditory examinations, and imaging studies. In a series of 421 patients harboring CPA meningiomas, 72 patients in whom there was dural involvement of the IAC were investigated. Total tumor resection was achieved in 86.1%. In 34 patients, opening of the IAC was required for total tumor removal; this procedure did not influence the patient functional outcome. Among patients with secondary involvement of the IAC, anatomical preservation of the facial and cochlear nerves was obtained in 94%, whereas among patients in whom the lesion arose from the dura in or at the IAC these values were 80 and 75%, respectively. Functional preservation of the seventh and eighth cranial nerves in cases of tumor extension within the IAC was 86 and 77%, respectively, whereas in cases in which the IAC was involved it was only 60%. In four of five patients in whom the tumor had its origin in the dura mater within the IAC, the seventh or eighth cranial nerve had to be sacrificed to achieve tumor removal because of the lesion's infiltrative behavior. Facial nerve reconstruction by sural grafting was performed in the same operative procedure.

CONCLUSIONS

Meningiomas of the CPA involving the IAC require special surgical management. Dural involvement of the IAC requires opening by using a diamond drill, a procedure that does not influence cranial nerve outcome. The increased rate of cranial nerve morbidity is attributed to the infiltrative behavior of these meningiomas. If affected nerve segments have to be sacrificed, immediate reconstruction enables satisfactory long-term results.

Intracranial Neuromuscular Choristoma: A Case Report and Literature Review

Neuromuscular choristoma (NMC) is an uncommon tumor that usually involves a large nerve trunk. Only 28 cases of NMC have been previously reported in the English-language literature, 17 of which involved cranial nerves. We report a new case of intracranial NMC that arose from a facial nerve at the cerebellopontine angle in a 44-year-old man. The patient was taken to surgery, where the lesion was found to involve the right facial nerve. The tumor was partially removed, and at the 2-year follow-up, the patient showed no sign of recurrence.

Differential diagnosis of intracranial lesions with high signal on T1 or low signal on T2-weighted MRI

Magnetic resonance imaging (MRI) is the preferred technique for examining intracranial pathology in the non-acute setting in most cases. The aim of this review is to demonstrate the imaging appearances on unenhanced spin-echo MRI of lesions that show characteristic, unusual signal changes, which occur due to the presence of fat, cholesterol, paramagnetic substances, rapidly flowing fluids, air, cortical bone or calcification. The nature of the MRI signal, together with the anatomical location of the lesion should allow the provision of a narrow differential diagnosis, before the use of intravenous contrast medium or additional imaging sequences.

Lipochoristomas (Lipomatous Tumors) of the Acoustic Nerve

Context.—Lipochoristomas (lipomatous choristomas) are rare tumors of the acoustic nerve (cranial nerve VIII/vestibulocochlear nerve) within the internal acoustic canal and sometimes the cerebellopontine angle, and are histogenetically believed to be congenital malformations. Their clinically indolent behavior has recently prompted a more conservative management protocol in a quest for maximal nerve/hearing preservation. This approach contrasts sharply with that for the common internal acoustic canal/cerebellopontine angle tumors, the neuroepithelial neoplasms (acoustic schwannomas and meningiomas), which behave more aggressively and have more prominent clinical manifestations. Owing to their rarity, the clinicopathologic features of cranial nerve VIII lipochoristomas have been obtained mainly through case reports.

Objective.—We present the clinicopathologic features of 11 cases of lipochoristomas of cranial nerve VIII.

Design.—The 11 cases were documented between 1992 and 2003. We performed complete clinical reviews with histologic, histochemical, and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples.

Results.—The patients were 8 men and 3 women with hearing loss of the right ear (5 patients) or the left ear (6 patients). No patient had bilateral tumors. All lipochoristomas histologically possessed mature adipose tissue admixed with varied amounts of mature fibrous tissue, tortuous thick-walled vessels, smooth muscle bundles, and skeletal muscle fibers, the latter verified with immunohistochemistry.

Conclusions.—The histomorphologic and immunophenotypic evidence showed that these tumors are better characterized as choristomas than as simple “lipomas,” as they have been labeled in the past. Their overall nonaggressive clinical nature in addition to the characteristic radiologic and histomorphologic findings are important clinicopathologic features for the pathologist to recognize and differentiate, especially during frozen section evaluations, in order to direct the neurosurgeon to a more appropriate conservative therapeutic intervention.

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.

Hemilingual spasm: a new neurosurgical entity? Case report

Hemilingual spasm is a little-known movement disorder, presenting as intermittent paroxysmal involuntary contractions of half of the tongue muscles. The authors report a case of hemilingual spasm caused by an arachnoid cyst. After marsupialization of the cyst, the patient's symptoms immediately resolved. There has been no recurrence of hemilingual spasm during the follow-up period of more than 40 months.

Arachnoid cyst of the fallopian canal: a surgical challenge

OBJECTIVE

Spontaneous cerebrospinal fluid (CSF) leaks from the fallopian canal are exceedingly rare, with only 6 reports appearing in the world literature. We report a seventh case that is unique in that it involves an arachnoid cyst of the fallopian canal and an associated facial nerve palsy.

STUDY DESIGN

Case report.

SETTING

International tertiary care referral center.

CONCLUSION

CSF otorhinorrhea associated with a facial nerve palsy may be indicative of an arachnoid cyst of the fallopian canal. These fistula are extremely rare. Surgical management involves sealing the fistula while preserving facial nerve function and is extremely challenging.

Cerebellopontine Angle Lipomas: Report of Four Cases and Review of the Literature

OBJECTIVE:

To define the management of internal acoustic meatus and cerebellopontine angle (CPA) lipomas according to their clinical, histological, and surgical characteristics.

METHODS:

We report four new cases of CPA lipomas diagnosed in the Department of Otorhinolaryngology–Head and Neck Surgery of Hôpital Pitié-Salpêtrière and review 94 cases reported previously in the literature.

RESULTS:

Lipomas represented 0.14% of CPA and internal acoustic meatus tumors. Localization was on the left side in 59.9%, on the right side in 37%, and bilateral in 3.1% of the patients. The diagnosis was confirmed radiologically in 33 of 98 patients, surgically in 60 patients, and by autopsy in 5 patients. The most frequent associated symptoms were of cochleovestibular origin, such as hearing loss (62.2%), dizziness (43.3%), and unilateral tinnitus (42.2%). Other associated symptoms involved the facial nerve (9%) or the trigeminal nerve (14.4%). Complete resection was performed in only 32.8% of the patients with frequent cranial nerve involvement. Frequent cranial nerve involvement was seen in 95.4% of all patients. After surgery, patient symptomatology was unchanged in 9.2% of the patients, and 50% were improved; however, new postoperative deficits occurred in two-thirds of the patients. Overall, 72.2% of the patients experienced new postoperative deficits such as hearing loss (64.8%). Preservation of hearing was possible in only 26% of the patients. Only 18% of patients were improved after surgery without any new postoperative deficits.

CONCLUSION:

Preoperative diagnosis of internal acoustic meatus/CPA lipomas is based on magnetic resonance imaging. The aim of surgery in these cases is not tumor removal but cranial nerve decompression or vestibular transection, and surgery is performed only in patients with disabling and uncontrolled symptoms.

Cerebellopontine angle epidermoids presenting with cranial nerve hyperactive dysfunction: pathogenesis and long-term surgical results in 30 patients

OBJECTIVE

To provide the characteristics and long-term surgical results of patients who present with cerebellopontine angle epidermoids and trigeminal neuralgia (TN) or hemifacial spasm.

METHODS

A total of 30 patients (23 women, 7 men) who presented with cerebellopontine angle epidermoids and TN (28 patients) or hemifacial spasm (2 patients) between 1982 and 1995 were reviewed, with emphasis being placed on the clinical manifestations, the mechanisms of symptom development, the long-term follow-up results, and the anatomic relationship between the tumor and the surrounding neurovascular structures.

RESULTS

The average age of the patients was 37.8 years at symptom onset and 49.3 years at the time of the operation. The tumor-nerve relationships were classified into four types: complete encasement of the nerve by the tumor, compression and distortion of the nerve by the tumor, compression of the nerve by an artery located on the opposite side of the unilateral tumor, and compression of the nerve by an artery on the same side of the tumor. Total resection was achieved in 17 patients (56.7%). Microvascular decompression of the respective cranial nerve was achieved in nine cases of direct arterial compression in addition to tumor removal. The symptom was relieved completely in all cases. In an average follow-up period of 11.5 years, three patients developed recurrent symptoms: two experienced tumor regrowth, and one had arachnoid adhesion.

CONCLUSION

Hyperactive dysfunction of the cranial nerves, especially TN, may be the initial and only symptom that patients with cerebellopontine angle epidermoids experience. The occurrence of TN at a younger age was characteristic of TN patients with epidermoids, in contrast to patients with TN due to a vascular cause. The symptom is elicited by compression of the nerve by the tumor per se, by an artery that is displaced to the nerve, or by both. Careful resection of the tumor, whose capsule occasionally is strongly adherent to the neurovascular structures, is necessary, and microvascular decompression to straighten the neuraxis should be performed in some cases to achieve a complete, permanent cure of symptoms with a low rate of recurrence.

[Epidemiologic studies of cerebellopontine angle tumors surgically treated in Maracaibo, Venezuela, in 1985-1999]

OBJECTIVE

To analyze the epidemiological, clinical and neuropathological data of cases of cerebellopontine angle (CPA) tumors.

MATERIAL AND METHODS

The clinical records, neuroimaging and neuropathological studies of 50 patients with diagnosis of CPA tumor operated in different hospitals of Maracaibo, Venezuela, during the lapse January 1st, 1985-December 31, 1999 were reviewed. The variables age, gender, side of the lesion and neuropathological diagnosis were analyzed.

RESULTS

A 2:1 female to male ratio was observed. Median age was 48 +/- 12.7 years. Acoustic neuromas (AN) represented 48% of the cases, whereas nonacoustic neuroma tumors (NANT) made up for the rest (52%). Meningiomas were the second more commonly diagnosed lesions, they constituted 32% of the cases. Meningiomas and AN were more frequent in women, their ratios being 7:1 and 1.6:1, respectively. In 60% of the cases the signs and symptoms became eloquent in patients of the fourth and fifth decades of life.

CONCLUSIONS

The difference between our results and the ones previously reported in the medical literature are due in part to the predominance of female patients in our series. Endocrinologic, genetic and biochemical factors could also be responsible; nevertheless, this does not constitute the objective of the present study.

Radiologic differentiation of intracranial epidermoids from arachnoid cysts

OBJECTIVE

Intracranial epidermoids (cholesteatomas) mimic arachnoid cysts in their radiologic characteristics, especially in the cerebellopontine angle. It is essential to differentiate the two conditions because they warrant different therapeutic interventions. The objective of this study is to elucidate the different radiologic characteristics of the conditions.

STUDY DESIGN AND SETTING

This was a retrospective study of 4 patients referred for a differential diagnosis and management of intracranial cystic lesions to the Departments of Neurotology/Neurosurgery and Neuroradiology in a tertiary referral university hospital.

PATIENTS

Four patients of different age groups with cystic intracranial lesions, diagnosed epidermoid or arachnoid cysts, were chosen. A retrospective analysis of their case charts, radiologic and surgical interventions, and follow-up records was undertaken.

METHODS

The imaging techniques used included computerized tomographic scans, magnetic resonance imaging (MRI) with T1, T2, proton-density, and gadolinium-enhanced T1 images. In addition, special MRI sequences were used that included fluid-attenuated inversion recovery and echo planar diffusion scanning. All the patients underwent an audiovestibular evaluation.

RESULTS

Both lesions are characteristically well demarcated and have a homogeneous low density, similar to cerebrospinal fluid on computerized tomographic scan, showing no contrast enhancement. On MRI, epidermoids and arachnoid cysts usually appear hypointense on T1-weighted images and hyperintense on T2-weighted images. On fluid-attenuated inversion recovery, an arachnoid cyst tends to follow cerebrospinal fluid intensity, whereas an epidermoid becomes hyperintense. There are occasions when an epidermoid may appear as a low-intensity lesion on fluid-attenuated inversion recovery. This dilemma is resolved with the use of echo planar diffusion scanning, on which an epidermoid remains bright.

CONCLUSION

The authors recommend the use of fluid-attenuated inversion recovery and diffusion sequence MRI when definitive radiologic diagnosis of cystic intracranial lesions becomes difficult with routine computerized tomographic scanning and MRI.

Cerebellopontine angle meningioma with a high jugular bulb

A cerebellopontine angle meningioma originating from the skull base over a high jugular bulb is quite rare. We report a case of a 68-year-old woman who had a right cerebellopontine angle meningioma with a prominent high jugular bulb. CT and MRI revealed a round tumour which attached to a bony prominence over the high jugular bulb. The apex of the jugular bulb was 3 mm higher than the floor of the internal auditory canal. The tumour was removed via a suboccipital retrosigmoid approach. The bony projection was drilled off carefully using a diamond drill; the jugular bulb became visible through the thinned bone. When a meningioma of this type is removed including bony changes, special attention is needed to avoid injury to the jugular bulb.

Diagnosis and Treatment of Lipomas of the Internal Auditory Canal

A Chinese woman came to the otolaryngology department with a complaint of a longstanding progressive left hearing loss and intractable tinnitus. A finding of asymmetry on sensorineural hearing loss and auditory brainstem response testing provided evidence of a retrocochlear lesion on the left side. Computed tomography and magnetic resonance imaging detected a tumor in the left internal auditory canal (IAC). In addition to these radiologic features, our suspicion of the possibility of an IAC lipoma was raised by the observation of multiple lipomas over the patient's trunk and limbs. The patient underwent a complete tumor resection via the translabyrinthine approach. Pathology confirmed the diagnosis of an IAC lipoma. Although we were not able to preserve the hearing in her left ear, the patient was satisfied that we had relieved her constant tinnitus. In this article, we review the particulars of this case and discuss the clinical, radiologic, and pathologic features of IAC lipomas.