Surgical treatment of epidermoid cysts of the cerebellopontine angle

Long term management of intracranial epidermoids balancing extent of resection and functional preservation in a 20 year institutional experience

Epidermoid lesions account for 1% of intracranial neoplasms. Surgical management is challenging due to their adhesion to critical neurovascular structures and tendency for recurrence. The current study examines surgical outcomes, extent of resection, and recurrence rates during long-term follow-up. A retrospective analysis was conducted on patients treated for epidermoid lesions between 2000 and 2021, focusing on clinical and radiological outcome and long-term symptom development. Among 55 patients (56.4% male), the majority harbored lesions in the cerebellopontine angle (75.3%). The mean age at surgery was 41.3 years, with an average follow-up of 82 months. Total removal was achieved in 61% of cases, with 75% of them remaining recurrence-free. In comparison, 35% of near-total removal and 25% of subtotal removal remained recurrence-free. Immediate symptom improvement was similar after total and non-total removal (12.6% vs. 10.5%), but long-term improvement was higher after total removal (43% vs. 27%). Transient cranial nerve deficits occurred in 25% of total and in 32% of non-total removal cases, with similar rates of minor complications. Total removal provided better long-term symptom control and lower recurrence rates without significantly increasing neurological deficits, supporting it as the preferred surgical strategy while maintaining functional preservation.

Complete resection of a giant epidermoid cyst of the occipital bone: case report and systematic review

Epidermoid cysts are uncommon accounting for less than 1% of all intracranial tumors. Among them, giant intradiploic epidermoid cysts of the posterior fossa i.e. those exceeding 5 cm are an even rarer entity. Here we report on the complete resection of a 7 cm posterior fossa epidermoid cyst involving the occipital bone in a 32-year-old female presenting with an acute on chronic exacerbation of headaches and vertigo. Complete resection including the cyst wall is crucial in preventing recurrence and malignant transformation. We add to limited existing data by reporting on the first systematic review to date assessing 25 cases of giant epidermoid cysts of the posterior fossa to discuss presentation, clinical and radiographic features and definitive management strategies.

Posterior fossa epidermoid tumors: a single-center study and proposed classification system

BACKGROUND

Epidermoid tumors of the cerebellopontine angle and posterior fossa account for approximately 1% of all intracranial tumors. Classifications that may guide surgical planning in the current neurosurgical practice are lacking. This study aimed to focus on the surgical outcome and suggest a classification system that may aid neurosurgeons in determining the goal of resection to minimize morbidity and mortality rates.

METHODS

The study population comprised patients who underwent surgery and follow-up for tissue-proven epidermoid tumors between 2015 and 2020. Patients' data, including demographic features, clinical symptomatology, the extent of surgical resection, and postoperative outcomes, were retrospectively evaluated. A new classification system was designed based on the anatomical-radiological findings and was evaluated in terms of clinical symptomatology, radiological features, surgical approach, and postoperative outcomes.

RESULTS

The patient population comprised 22 women (57.9%) and 16 men (42.1%), with a mean age of 34.9 years. A practical classification system based on the radiological-anatomical vertical (1, 2, and 3) and horizontal (a, b, and c) tumor extensions was designed. No significant differences were found in the patients in terms of sex/age. The most commonly observed symptom was gait disturbance (34.2%). The preoperative tumor diameter was significantly larger in the subtotal resection (STR) group than in the gross total resection (GTR) and near-total resection (NTR) groups. Significantly more cistern involvement was observed in the STR group than in the GTR group. The GTR, NTR, and STR rates were higher in grade 1, 3, and 2 cases, respectively. The subgroup 'a' was correlated with higher resection rates (GTR and NTR), whereas the subgroup 'b' was correlated with STR.

CONCLUSIONS

Our suggested classification system represents a simple and practical model that may guide neurosurgeons in predicting the goal of resection during surgical planning and in minimizing potential morbidity.

Epidermoid Cyst of the Brainstem in 3-Year-Old Child: A Rare Case Report

Epidermoid cysts are infrequent lesions occupying the intracranial space, comprising approximately 1-2% of all intracranial tumors. Brainstem epidermoids are exceptionally uncommon in children; up until now, only a few scattered case reports have been documented in the literature regarding this unique location. These cysts commonly arise from the inclusion of ectodermal elements during neural tube closure. Complete excision of these cysts is challenging due to their close proximity and adherence to the brainstem, which makes it difficult to achieve. As a result, recurrence of the cysts is not uncommon. We have reported a rare case of a 3-year-old with a 5-month history of progressive headache, imbalance while walking and progressive weakness in his right upper limb and lower limb along with difficulty in swallowing. On MRI Brain imaging study he had a pre-pontine epidermoid with intra-axial extension in the pons. The patient underwent retro-sigmoid/suboccipital craniotomy and microsurgical excision of the tumor, including the tumor capsule. After completing the surgery, the cavity was irrigated using a solution containing hydrocortisone and Ringer lactate to prevent the occurrence of aseptic meningitis. In the postoperative, the patient recovered without any complications, as all symptoms showed immediate improvement, and the lower cranial nerves returned to normal functioning.

Fully neuroendoscopic resection of cerebellopontine angle tumors through a retrosigmoid approach: a retrospective single-center study

The objective of this study is to preliminarily investigate the surgical safety, efficacy, techniques, and clinical value of fully neuroendoscopic surgery for the resection of cerebellopontine angle (CPA) tumors via a retrosigmoid approach. The clinical data of 47 cerebellopontine angle area (CPA) tumors that were treated by full neuroendoscopic surgery from June 2014 to June 2023 were retrospectively analyzed. The efficacy and advantages of the surgical techniques were evaluated based on indicators such as duration of the surgery, neuroendoscopic techniques, intraoperative integrity of nerves and blood vessels, extent of tumor resection, outcomes or postoperative symptoms, and incidence of complications. The 47 cases of cerebellopontine angle tumors include 34 cases of epidermoid cysts, 7 cases of vestibular schwannomas, and 6 cases of meningiomas. All patients underwent fully neuroendoscopic surgery. Twenty tumors were removed using the one-surgeon two-hands technique, and 27 tumors were removed using the two-surgeons four-hands technique. The anatomical integrity of the affected cranial nerves was preserved in all 47 cases. None of the patients suffered a postoperative hemorrhage, cerebrospinal fluid leak, and aseptic or septic meningitis, or died. The rate of total tumor resection was 72.3% (34/47), and the symptom improvement rate was 89.4% (42/47). All patients were followed up for 2 to 12 months, and none died nor showed any signs of tumor recurrence. By analyzing 47 fully neuroendoscopic resections of CPA tumors using the posterior sigmoid sinus approach in our center, we believe that such method allows complete, safe, and effective resection of CPA tumors and is thereby worthy of clinical promotion.

Open surgery vs. stereotactic radiosurgery for tumour-related trigeminal neuralgia: A systematic review

BACKGROUND

Secondary trigeminal neuralgia is a facial pain in trigeminal nerve dermatome caused by an underlying disease, such as cerebellopontine angle tumours. Treatment options to relieve the pains were surgical tumour resection and stereotactic radiosurgery of the tumour or trigeminal nerve. This study aims to review the efficacy of open surgery and stereotactic radiosurgery and recommend the treatment of choice for secondary trigeminal neuralgia due to cerebellopontine angle tumours.

METHOD

The inclusion criteria were studies covering patients with trigeminal neuralgia associated with cerebellopontine angle tumours that were treated with either open surgery or stereotactic radiosurgery and reported pain outcomes after treatment. Non-English articles or studies with a population of less than five were excluded. We systematically searched studies from PubMed, Ebscohost, and Cochrane Library from inception until December 20, 2021. Several works of literature from manual search were also added. Selected articles were appraised using a critical appraisal tool for prognostic studies.

RESULT

Included articles were 26 retrospective studies and one prospective study comprising 517 patients. Of 127 schwannomas, 226 epidermoids, 154 meningiomas, and ten other tumours, 320 cases received surgical tumour excision with or without MVD, 196 had tumour-targeted radiosurgery, and 22 underwent nerve-targeted radiosurgery. In surgical series, 92.2 % gained pain improvement, 2.8 % were unchanged, and 4.5 % had recurrence; none of the patients had worsened outcomes. In cases treated with tumour-targeted radiosurgery, the improvement rate was 79.1 %, unchanged at 14.3 %, recurrence at 26.5 %, and worse symptoms rate after the intervention was 6.6 %. Six patients with recurrent pain after tumour-targeted radiosurgery received secondary nerve-targeted radiosurgery with improved outcomes. Only one patient in our review underwent primary nerve-targeted radiosurgery, and the result was satisfactory. One study treated 15 patients with a single session of tumour-targeted and nerve-targeted radiosurgery, with an improvement rate of 93.3 % and a recurrence rate of 21.4 %.

CONCLUSION

Open surgery releasing the nerve root from compressive lesions is advocated to be the first-line treatment to gain satisfactory outcomes. Total removal surgery is recommended if possible. Nerve-targeted radiosurgery should be reserved as a secondary treatment for recurrent cases.

Intracranial epidermoid cysts: benign entities with malignant behavior: experience with 36 cases

Intracranial epidermoid cysts are benign slow-growing ectodermal inclusions that account for less than 1% of all intracranial tumors. We retrospectively reviewed 36 such cases to evaluate the demographic characteristics, clinical manifestations, anatomical distribution, surgical management, and treatment outcome of these tumors. Additionally, we sought to identify the relationship between median or paramedian cistern tumor localization and clinical parameters, such as recurrence risk, hospitalization duration, and postoperative complication rates. The most frequently observed neurological symptoms were transient headaches (77.8%), dizziness (36.1%), CN VII palsy (19.4%), CN VIII hearing difficulty (19.4%) and cerebellar signs (19.4%). The most common surgical approaches included retrosigmoid (36.1%), subfrontal (19.4%) and telovelar (19.4%) approaches; gross total resection was feasible in 83.3% of cases. The postoperative complication rate was 38.9%. Tumors were more frequently found in the paramedian cisterns (47.2%), followed by the median line cisterns (41.6%). Multivariate analysis revealed that postoperative hydrocephalus and age < 40 years were prognostic factors for tumor recurrence. Median-like tumor location was a risk factor for the presence of symptomatic hydrocephalus both preoperatively and postoperatively, increasing the likelihood of protracted hospitalization (> 10 days). Despite their benign histopathological nature, these tumors have an important clinical resonance, with a high rate of postoperative complications and a degree of recurrence amplified by younger age and hydrocephalus.

Spectrum of intracranial and spinal epidermoids including unusual locations and imaging findings: A pictorial review

Intracranial and spinal epidermoids are benign slow-growing congenital lesions. They are predominantly intradural, extra-axial in location, with intra-axial locations (intra-parenchymal and spinal intramedullary) being rare. The most common locations of intradural epidermoids are cerebellopontine angle cistern followed by supra- and para-sellar regions, and fourth ventricle. Less common locations include inter-hemispheric fissure, sylvian fissure, lateral ventricle, intracerebral, velum interpositum cistern, superior cerebellar cistern and pineal gland. They can also be extradural, usually arising in the diploic space of the calvaria, though they are less common. Magnetic resonance imaging is the primary modality for diagnosis and knowing the extent of the lesion. In this pictorial review, we intend to illustrate their classical and unusual locations, atypical imaging findings including calcifications, rare complications like haemorrhage or spontaneous rupture.

Neurosurgical Management of Skull Base Epidermoid Tumors in Children

Epidermoid tumors (ET) are congenital and benign tumors that develop from de ectoderm during neurogenesis. In the skull base, these lesions can insinuate themselves into several intracranial compartments by filling the subarachnoid space, and possibly affecting some important structures, like the brainstem, cerebellopontine angle, the pituitary in the middle fossa, and others. In the pediatrics skull base tumors, the ET represents 7-9%, being very rare. The surgical perspective of these cases is dependent on the extension of the resection. We presented two cases of total and near-total resection of ETs in the pediatric skull base, with successful outcomes.

Endoscopic Endonasal Surgery for Dermoid Cysts Arising From the Middle Cranial Fossa Floor: A Rare Case Series

OBJECTIVE

Dermoid cysts (DCs) are congenital, slowly growing, and may cause nervous system symptoms. Related literature is limited and mainly includes case reports. We report a case series of DCs originating from the middle cranial fossa floor (MCFF) and investigate their demographic information, clinical characteristics, imaging findings, surgical procedures, and prognostic outcomes.

METHODS

We reviewed the patients with DCs arising from the MCFF undergoing endoscopic endonasal surgery (EES) in our center between 2012 and 2022.

RESULTS

A total of 5 patients with DCs were enrolled (2 males and 3 females), with a mean age of 46.2 years at the onset. All DCs originated from the MCFF with 1 case involving the middle cranial fossa bone and another 1 case affecting the dura mater. One (20.0%) patient had neurological involvement. After admission, all patients received EES with a total resection rate of 100.0% (5 of 5). After a median follow-up of 73.2 months, all patients achieved complete clinical and radiological improvements. No surgical-related complications or relapses were observed during the long-term follow-up.

CONCLUSION

Endoscopic endonasal surgery is considered a safe and effective approach for the treatment of DCs in the MCFF. A larger sample size and longer follow-up time are needed.

The endoscopic-assisted approach versus the microscopic only approach in resection of cerebellopontine angle epidermoids: a 5-year retrospective study

Background

The endoscopic-assisted technique has been utilized with various intracranial lesions with many approaches. In the cerebellopontine angle (CPA), the technique has been used to combine the benefits of the operating microscope and the endoscope. In this study, we highlight the use of the endoscopic-assisted technique in resection of CPA epidermoid tumors to ensure a total resection, decrease complications and protect the neurovascular tangles.

Results

In the endoscopic-assisted group, only 18.8% of the patients had post-operative residual in the post-operative MRI. However, in the microscopic only group 56.3% of the patients had post-operative residual. Consequently, there is a statistically significant difference regarding the post-operative residual between the two groups.

Conclusions

The endoscopic-assisted approach is superior to the microscopic only approach in the excision of CPA epidermoids and minimizing the post-operative residual and the recurrence.

Cerebellopontine Angle Epidermoids: Comparative Results of Microscopic and Endoscopic Excision Using the Retromastoid Approach”

Background Densely packed neurovascular structures, often times inseparable capsular adhesions and sometimes a multicompartmental tumor extension, make surgical excision of cerebellopontine angle epidermoids (CPEs) a challenging task. A simultaneous or an exclusive endoscopic visualization has added a new dimension to the classical microscopic approaches to these tumors recently.

Methods Eighty-six patients (age: 31.6 ± 11.7 years, M:F = 1:1) were included. Nineteen patients (22.1%) had a multicompartmental tumor. Tumor extension was classified into five subtypes. Sixty-two patients underwent a pure microscopic approach (72%) out of which 10 patients (16%) underwent an endoscope-assisted surgery (11.6%) and 24 patients (28%) underwent an endoscope-controlled excision. Surgical outcomes were retrospectively analyzed.

Results Headache (53.4%), hearing loss (46.5%), and trigeminal neuralgia (41.8%) were the leading symptoms. Interestingly, 21% of the patients had at least one preexisting cranial nerve deficit. Endoscopic assistance helped in removing an unseen tumor lobule in 3 of 10 patients (30%). Pure endoscopic approach significantly reduced the hospital stay from 9.2 to 7.3 days (p = 0.012), and had a statistically insignificant yet a clearly noticeable lesser incidence of subtotal tumor excision (0 vs. 10%, p = 0.18) with comparable cranial nerve deficits but with a higher postoperative cerebrospinal fluid (CSF) leak rate (29% vs. 4.8%, p = 0.004).

Conclusion Endoscope assistance in CPE surgery is a useful addition to conventional microscopic retromastoid approach. Pure endoscopic excision in CPE is feasible, associated with a lesser duration of hospital stay, better extent of excision in selected cases, and it has a comparable cranial nerve morbidity profile albeit with a higher rate of CSF leak.

A Case of Dermoid Cyst Arising in the Temporal Lobe

Intracranial dermoid cysts are rare congenital lesions that result from abnormal sequestration of ectodermal cells during neural tube formation. These tumors are especially rare in lateral areas such as in the temporal lobe. In this study, we report a case of dermoid cyst located in the right temporal lobe. A 50-year-old man was referred for further treatment of a tumor. CT revealed a low-density mass lesion in the right temporal lobe, with calcification. MRI showed the lesion with high signal intensity on diffusion-weighted imaging, high-low mixed signal intensity on T1-weighted imaging, and iso-high signal mixed intensity on T2-weighted imaging; the capsule was enhanced with gadolinium. Differential diagnosis included dermoid cyst, epidermoid cyst, teratoma, and neurenteric cyst. We decided to perform surgery for the improvement of his symptom, histopathological diagnosis, and radical cure. A right temporal craniotomy was performed, and the tumor was found adherent to the surrounding brain tissue. The tumor was completely removed under subpial dissection. Hair was confirmed in the tumor content. On histopathology, the cyst wall was lined with stratified squamous epithelium, sebaceous glands, small vessel aggregates, and inflammatory infiltrate. Keratinized material and hair were found in the lumen. The patient was discharged 7 days after surgery with no new neurologic deficits. This case was unusual in terms of the effect of gadolinium enhancement on MRI, and the presence of adipose tissue and calcification were useful for diagnosis. It is vital to consider prevention of chemical meningitis due to intrathecal dissemination of the tumor content intraoperatively.

Long-term surgical oncological and functional outcome of large spetroclival and cerebellopontine angle epidermoid cysts: a multicenter study

Cranial nerve (CN) disorders are the foremost symptoms in cerebellopontine angle (CPA) and petroclival area (PCA) epidermoid cysts (EC).The aim of this work was to  assess the long-term surgical results on CN function and tumor control in these patients EC. We performed a retrospective cohort study about 56 consecutive patients operated on for a CPA or PCA EC between January 2001 and July 2019 in six participating French cranial base referral centers. Sixteen patients (29%) presented a PCA EC and 40 a CPA EC (71%). The median clinical and radiological follow-up was 46 months (range 0-409). Preoperative CN disorders were present in 84% of patients (n = 47), 72% of them experienced CN deficits improvement at the last follow-up consultation (n = 34): 60% of cochlear and vestibular deficits (n = 9/15 in both groups), 67% of trigeminal neuralgia (n = 10/15), 53% of trigeminal hypoesthesia (n = 8/15), 44% of lower cranial nerve disorders (n = 4/9), 38% of facial nerve deficits (n = 5/8) and 43% of oculomotor deficits (n = 3/7) improved or were cured after surgery. New postoperative CN deficits occurred in 48% of patients (n = 27). Most of them resolved at the last follow-up, except for cochlear deficits which improved in only 14% of cases (n = 1/7). Twenty-six patients (46%) showed evidence of tumor progression after a median duration of 63 months (range 7-210). The extent of resection, tumor location, and tumor size was not associated with the occurrence of new postoperative CN deficit or tumor progression. A functional nerve-sparing resection of posterior fossa EC is an effective strategy to optimize the results on preexisting CN deficits and reduce the risk of permanent de novo deficits.

Dysfunctions and anatomical relationships of cranial nerves in epidermoids of the cerebellopontine angle

OBJECTIVE

To evaluate the correlation of neurological symptoms with anatomical relationships of cranial nerves, lesions and vessels in patients with epidermoids of the cerebellopontine angle.

MATERIAL AND METHODS

We analyzed neurological symptoms, magnetic resonance data, intraoperative findings and postoperative functional outcomes in 25 patients (14 females and 11 males aged 22-77 years) with epidermoids of the cerebellopontine angle.

RESULTS

Cranial nerve dysfunctions were noted in 15 patients. Involvement of cochlear (n=9) and trigeminal (9 cases including 4 ones with sensory impairment and 5 patients with neuralgia) nerves was the most common. There were 10 patients with ataxia, hemiparesis and seizures without cranial nerve dysfunction. In 15 patients, epidermoids spread to supratentorial space and contralateral cerebellopontine angle. Lesion-induced brainstem compression was found in 22 cases. Cranial nerves and cerebellar arteries were partially or completely enclosed by lesion in all cases. Severe compression and dislocation of the nerve root entry/exit zone were found in all cases. One patient with trigeminal neuralgia had vascular compression of trigeminal nerve caused by superior cerebellar artery. Total resection was achieved in 16 patients. Small capsule remnants were left on vessels, nerves or brainstem in 9 patients. Postoperative complete or partial restoration of cranial nerve functions was noted in 11 cases. Deterioration of preoperative neurological deficit in 4 patients and postoperative neurological symptoms de novo in 3 patients were temporary.

CONCLUSION

Cranial nerve dysfunctions are caused by compression of the nerve root entry/exit zones by epidermoids of the cerebellopontine angle. Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression. Vascular decompression should be performed in patients with trigeminal neuralgia.

Long-term surgical outcomes of intracranial epidermoid tumors: impact of extent of resection on recurrence and functional outcomes in 63 patients

OBJECTIVE

The authors' objective was to reevaluate the role of microsurgery for epidermoid tumors by examining the associations between extent of resection (EOR), tumor control, and clinical outcomes.

METHODS

This was a retrospective study of patients with microsurgically treated intracranial epidermoid tumors. The recurrence-free and intervention-free rates were calculated using the Kaplan-Meier method. EOR was graded as gross-total resection (GTR) (total resection without residual on MRI), near-total resection (NTR) (a cyst lining was left in place), subtotal resection (STR) (> 90% resection), and partial resection (PR) (any other suboptimal resection) and used to stratify outcomes.

RESULTS

Sixty-three patients with mean clinical and radiological follow-up periods of 87.3 and 81.8 months, respectively, were included. Sixteen patients underwent second resections, and 5 underwent third resections. The rates of GTR/NTR, STR, and PR were 43%, 35%, and 22%, respectively, for the initial resections; 44%, 13%, and 44% for the second resections; and 40%, 0%, and 60% for the third resections (p < 0.001). The 5- and 10-year cumulative recurrence-free rates after initial resection were 64% and 32%, respectively. When stratified according to EOR, the 10-year recurrence-free rate after GTR/NTR was marginally better than that after STR (61% vs 35%, p = 0.130) and significantly better than that after PR (61% vs 0%, p < 0.001). The recurrence-free rates after initial microsurgery were marginally better than those after second surgery (p = 0.102) and third surgery (p = 0.065). The 5- and 10-year cumulative intervention-free rates after initial resection were 91% and 58%, respectively. When stratified according to EOR, the 10-year intervention-free rate after GTR/NTR was significantly better than that after STR (100% vs 51%, p = 0.022) and PR (100% vs 27%, p < 0.001). The 5-year intervention-free rate after initial surgery was marginally better than that after second surgery (52%, p = 0.088) and significantly better than that after third surgery (0%, p = 0.004). After initial, second, and third resections, permanent neurological complications were observed in 6 (10%), 1 (6%), and 1 (20%) patients, respectively. At the last follow-up visit, 82%, 23%, and 7% of patients were free from radiological recurrence after GTR/NTR, STR, and PR as the initial surgical procedure, respectively.

CONCLUSIONS

GTR/NTR seems to contribute to better disease control without significantly impairing functional status. Initial resection offers the best chance to achieve better EOR, leading to better disease control.

Endoscopic Keyhole Approach for Intracranial Epidermoid

Objective  In contemporary neurosurgical practice, keyhole endoscopic approach has established its role in various neurosurgical pathologies. Intracranial epidermoid is an ideal pathology for endoscopic keyhole approach as epidermoid is well encapsulated, extra-axial, avascular, and easily suckable. The objective of this study is to share our experience of endoscopic keyhole approach for intracranial epidermoids at various locations as a new minimally invasive neurosurgical approach to deal with these lesions. Materials and Methods  We conducted a retrospective study on 26 patients who underwent keyhole pure endoscopic excision of intracranial epidermoid between July 2015 and December 2019. Patient's demographics, clinical features, radiological imaging, and postoperative complications were noted. Follow-up outcome of preoperative symptoms and postoperative complications were also analyzed. Results  The mean age of the study population was 30.5 years with a mean follow-up of 30 months. The common presenting features were headache, hearing loss, and trigeminal neuralgic pain. Gross total resection was achieved in 73.1% cases, while near total resection and subtotal resection were achieved in 19.2 and 7.7% cases, respectively. In the follow-up, maximal improvement was seen in trigeminal neuralgic pain (83%) and headache (66.7%). Major postoperative complications were facial nerve paresis, lower cranial nerve paresis, and transient facial hypoesthesia, most of which improved over time. None of the patients required resurgery till date. Statistical Analysis  Patients' data were analyzed using SPSS software version 23 (Statistical Package for Social Sciences, IBM, Chicago, United States). Conclusion  This study demonstrates that with careful patient selection, endoscopic keyhole excision of epidermoid is a good alternative to conventional microsurgical excision with comparable surgical and functional outcomes.

Importance of appropriate surgical approach selection for radical resection of cerebellopontine angle epidermoid cysts with preservation of cranial nerve functions: our experience of 54 cases

BACKGROUND

Although many reports state that only the lateral suboccipital retrosigmoid approach (LSO) should be used for removal of cerebellopontine angle (CPA) epidermoid cysts, it is preferable to use various surgical approaches as appropriate for each patient, for radical resection with an optimal operative field under direct visualization, and for the preservation of cranial nerve (CN) functions. In the present study, we hence focused on the importance of surgical approach selection for removal of CPA epidermoid cysts and analyzed the results of CPA epidermoid cysts after surgery in our series.

METHODS

Fifty-four patients who underwent surgery for CPA epidermoid cysts were retrospectively analyzed, regarding their surgical approaches, removal rates, preservation rates of CN function 1 year after surgery, and recurrence. Surgical approaches were selected for patients according to the size and extension of the tumor.

RESULTS

Surgical approaches consisted of LSO (20 cases), anterior transpetrosal approach (ATP; 3 cases), combined transpetrosal approach (27 cases), and ATP + LSO (4 cases). Mean tumor content removal and capsule removal rates were 97.4% and 78.3%, respectively. Preservation rates of facial nerve function and useful hearing were 94.4% and 90.7%, respectively. The mean postoperative follow-up time was 62.8 months, and there were two cases of recurrence requiring reoperation about 10 years after surgery.

CONCLUSIONS

For CPA epidermoid cyst surgeries, selection of the appropriate surgical approach for each patient and radical resection with an optimal operative field under direct visualization enable tumor removal without the need for reoperation for a long time, with preservation of CN functions.

Analysis of Giant Intraventricular and Extraventricular Epidermoids, Defining Risk Factors for Recurrence, an Institutional Experience

Background:

Multicompartmental intraventricular epidermoids behave differently from multicompartmental extraventricular lesions and localized lesions during its management. Few studies are available which have analyzed risk factors separately in these groups of cases for recurrence of these lesions and time to recur.

Materials and Methods:

In this retrospective observational study, 72 cases of intracranial epidermoid were treated over a span of 7 years. Cases were categorized into three groups. Group 1 comprised 15% (11/72) of cases with intraventricular multicompartmental, Group 2 with 22% (16/72) extraventricular giant tumors with multicompartmental involvement and size >4.5 cm, and Group 3 comprised 63% (45/72) of patients with lesions <4.5 cm and localized. Data pertaining to demography, clinical and radiological features, surgery performed, postoperative complication, histology, and follow-up were obtained from medical records available in the institute.

Results:

The average duration to treat was 1.86 ± 0.52 (standard deviation [SD]) years, with headache as a major complaint in all the groups. Combined endoscope-assisted microsurgery was performed in 38.8% (28/72), microsurgery in 54.1% (39/72), and endoscopic excision in 6.9% (5/72) of cases. Tumor calcification was found in 23.6% (17/72) and preoperative capsular enhancement was seen in 19.4% (14/72) which persisted in 79% (11/14) of cases postoperatively on subsequent follow-up suggesting recurrence. On stepwise logistic regression analysis, preoperative capsular enhancement was a strong predictor of recurrence of tumor (P = 0.001). The average follow-up was 46 ± 14.92 (SD) months in Group 1, 52.34 ± 11.45 (SD) months in Group 2, and 63.36 ± 18.42 (SD) months in Group 3.

Conclusion:

Although the intracranial epidermoid is known to recur after long interval, tumor with specific characteristics can recur in short span of 5–6 years. Tumor characteristics such as preoperative capsular enhancement, multicompartmental distribution in vertebrobasilar territory, large size, and presence of calcification are strong predictors for recurrence. Performing endoscope-assisted microsurgery can decrease the postoperative morbidities but does not reduce the recurrence risk.

Surgical management of cerebellopontine angle epidermoid cysts: an institutional experience of 10 years

BACKGROUND

Cerebellopontine angle (CPA) epidermoids, although of benign nature, are of considerable neurosurgical interest because of their close proximity and adherence to the cranial nerves and brain stem. In this paper, we describe our experience and attempt to correlate the final outcomes with the extent of surgical removal. The main objectives were to study various modes of surgical management of CPA epidermoids with regard to removal and preservation of the cranial nerves and also to evaluate the role of endoscopic assisted microsurgical excision thereby minimizing recurrences. This case series is one of the largest series reported so far worldwide.

MATERIALS AND METHODS

From 2006 to 2016, 139 patients with CPA epidermoids were operated at Grant Medical College and J. J. Hospital, Mumbai. All patients underwent detailed magnetic resonance imaging (MRI) of brain. Lesions were classified according Rogelio Revuelta-Gutiérrez et al. with respect to their anatomic extent: grade I- within the boundaries of the CPA, grade II- extension to the suprasellar and perimesencephalic cisterns, and grade III-parasellar and temporomesial region involvement. Retrosigmoidal and sub temporal approaches were taken to excise the lesions. Endoscopic assisted microsurgical excision was done in cases with extensions beyond the CPA. Patient follow-up was based on outpatient repeated brain MRI studies.

RESULTS

The mean duration of symptoms before surgery was 42 months (range, 2 months to 6 years). The mean follow-up period was 27 months (range, 2-60 months). The main presenting sympt om was headache in 69% (96/139) of the cases and trigeminal neuralgia in 30% cases was the second most common cause of consultation. Seventy-five percent of patients had some degree of cranial nerve (CN) involvement. Retrosigmoid approach was taken in 92% patients and 7 patients with supratentorial extension were operated by combined retrosigmoidal and subtemporal approach. Endoscopic assisted microsurgical excision was done in 40% cases. Use of angled views by an endoscope helped to excise residual tumor in 47 (83%) patients. Complete excision was achieved in 67% of cases. In 33% patients, small capsular remnants could not be removed completely because of their adherence to vessels, brainstem and cranial nerves. Compared with their preoperative clinical status, 74% improved and 20% had persistent cranial nerve deficits in the first year of follow up.

CONCLUSIONS

Epidermoid cysts are challenging entities in current neurosurgery practice due to tumor adhesions to neurovascular structures. Meticulous surgical technique with the aid of neurophysiological monitoring is crucial to achieve safe and effective total or subtotal removal of these lesions. A conservative approach is indicated for patients in whom the fragments of capsule is adhered closely to blood vessels, nerves, or the brainstem, in order to avoid risk of serious neurological deficits related to an inadvertent damage of these structures. Use of angled views by endoscope at the conclusion of the surgery may assure the surgeon of total removal of the tumor.

Sudden Death Due to a Cerebellopontine Angle Epidermoid Cyst: Case Report

Epidermoid cyst of the brain is a rare benign embryonal tumor. It has an excellent prognosis because of its slow-growing nature. Clinically, symptoms are variable and depend on the location of the cyst. Sudden death may occur as a result of lethal complications because of the tumor growth, but it is still rare. In this article, we present a rare case of sudden unexpected death of a 58-year-old man, with no neurologic history, due to an epidermoid cyst of the brain diagnosed at autopsy.

Recurrence of ruptured intracranial epidermoid cyst - A rare case report and presentation

INTRODUCTION

Intracranial epidermoid cysts are congenital tumors that develop from ectodermal remnants during neuroembryogenesis between the third and fifth weeks of gestation. These tumors are benign and usually present with local mass effect. Here, we present a rare case of ruptured intracranial epidermoid cyst with recurrence.

PRESENTATION OF CASE

A 55 years old male patient was brought to emergency with a history of headache and loss of consciousness for 1 h. Radiological imaging showed the features suggestive of ruptured intracranial epidermoid cyst which was operated. Two years later the patient re-presented with headache for 4-5 days where repeat MRI revealed recurrence of the tumor.

DISCUSSION

Epidermoid cysts are very slow growing tumor at a linear rate due progressive accumulation of normally dividing epidermal cells. These tumors often reach a large size before the onset of symptoms. At times, the tumor capsule may show infiltration to the brain parenchyma and tight adherence to neurovascular structures which leads to the incomplete removal of the tumor capsule leading to recurrence of tumor.

CONCLUSION

Rupture of intracranial epidermoid cyst is a rare phenomenon and recurrence of this tumor in patients is even infrequent.

Cerebellopontine Angle Epidermoid Cysts: Surgical Treatment Outcome

Background  Epidermoid cysts (ECs)are an uncommon slowly growing congenital lesions. The cerebellopontine angle (CPA) is the most common site. Surgical management for these lesions remains challenging due to the high-adherence of the cyst capsule to the surrounding structures and its tendency to present with invasion of multiple cisterns.

Objective The aim of this study was to evaluate the clinical and radiological outcome of surgically treated ECs in the CPA region.

Materials and Methods This is a retrospective study conducted on patients presenting with symptomatic CPA ECs. Clinical outcome was assessed in terms of improving or worsening of the presenting symptoms. Radiological outcome was assessed by comparing the tumor size, brainstem, and cerebellar compression in the preoperative and postoperative images.

Results In this study, 18 patients were included. All cases were operated upon by microsurgical evacuation of the cyst contents and excision of the nonadherent parts of the capsule. On admission, cranial nerve symptoms predominated. Improvement or resolution of preoperative deficits was seen in 15 patients. Preoperative symptoms worsened in two and new postoperative symptoms occurred in one patient. Seven patients needed additional ventriculoperitoneal (VP) shunt in the same setting due to the presence of hydrocephalus. During the follow-up period, symptomatic recurrence occurred in one patient, while asymptomatic recurrence occurred in one patient.

Conclusion Surgical management of CPA ECs, leaving remnants of the capsule on cranial nerves and brain stem can be considered as a relatively safe surgical procedure with a good clinical outcome and low-recurrence risks.

Microsurgical Resection of the Epidermoid Tumor in the Cerebellopontine Angle

In this video, we demonstrate epidermoid tumor microsurgical resection of the cerebellopontine angle (CPA) performed by the senior author (K.I.A.). Epidermoid tumors arise from ectoderm trapped within/displaced into the central nervous system. They show predilection for CPA Angle (up to 40%), 4th ventricle, suprasellar region, and spinal cord. 1 They are the 3rd most common CPA tumor, comprising approximately 7% of CPA pathology. CPA lesions can produce 5th and 7-12th cranial nerve neuropathies. 2 3 4 Recurrent episodes of aseptic meningitis caused by cyst content rupture may occur. Symptoms include fever, meningeal irritation, and hydrocephalus. A 26-year-old female presented with headaches. Head magnetic resonance imaging (MRI) revealed right CPA tumor with brain stem compression ( Fig. 1 , A - C ). There was evidence of restricted diffusion in diffusion-weighted imaging, typical of epidermoid tumor. Surgery was performed in prone position with head turned 25 degrees to the ipsilateral side using retrosigmoid craniotomy. 5 Tumor was ventral to the 7th and 8th cranial nerve complexes, between the 5th nerve as well as toward the brainstem. The surgical plan was gross total resection with tumor capsule resection to prevent recurrence. 6 (Small residuals can be left behind when capsule is adherent to critical structures.) Tumor was adherent to brain stem perforators which were preserved using meticulous dissection. Cranial nerves and vascular structures were also left intact. We irrigated with antibiotic saline and used perioperative treatment to prevent aseptic meningitis. The pathohistological diagnosis revealed epidermoid tumor cyst. Postoperative MRI revealed complete resection ( Fig. 1 , D - F ). The patient recovered fully and was neurologically intact. The link to the video can be found at: https://youtu.be/LyWl-KZUSGY .

Primary Petrous Apex Epidermoids With Skull Base Erosion

OBJECTIVE

To describe the clinical course and treatment outcomes for patients with petrous apex epidermoid with skull base erosion.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary-care academic center.

PATIENTS

Patients surgically managed for petrous apex epidermoids at a single-tertiary care institution from 2001 to 2017.

INTERVENTIONS

Surgical management of primary petrous apex epidermoids.

MAIN OUTCOME MEASURES

The presenting symptoms, imaging, pre- and postoperative clinical course, and complications were reviewed.

RESULTS

Seven patients were identified. The most common presenting symptoms included: sudden sensorineural hearing loss (n = 3), headaches (n = 1), vertigo (n = 2), and facial paralysis/paresis (n = 2). An epidermoid was discovered in two patients as an incidental finding after a head trauma and one patient after admission for altered mental status and meningitis. Two patients presented with complete facial paralysis (House-Brackmann 6/6). Preoperative normal hearing (pure-tone average < 25 db) was identified in three patients and serviceable hearing (pure-tone average 25-60 dB) in one patient. Three patients with nonserviceable hearing underwent a transcochlear or transotic approach. The remaining four patients underwent an attempted hearing preservation approach. Postoperatively, one patient developed delayed facial paralysis, improving within 3 months. Hearing was preserved in three patients. Two patients developed recurrence of disease within 4 and 7 years respectively.

CONCLUSIONS

Surgical management of aggressive petrous apex epidermoid is effective to preserve facial function and prevent recurrence. In our series different surgical approaches were used with variable outcomes.

Endoscopic endonasal resection of epidermoid cysts involving the ventral cranial base

OBJECTIVE

Epidermoid cysts (ECs) commonly extend to involve the ventral cisterns of the cranial base. When present, symptoms arise due to progressive mass effect on the brainstem and adjacent cranial nerves. Historically, a variety of open microsurgical approaches have been used for resection of ECs in this intricate region. In recent years, the endoscopic endonasal approach (EEA) has been proposed as an alternative corridor that avoids crossing the plane of the cranial nerves. To date, there is a paucity of data in the literature regarding the safety and efficacy of the EEA in the treatment of ECs of the ventral cranial base.

METHODS

The authors reviewed a prospectively acquired database of EEAs for resection of ECs over 8 years at Weill Cornell, NewYork-Presbyterian Hospital. All procedures were performed by the senior authors. Standardized clinical and radiological parameters were assessed before and after surgery. Statistical tests were used to determine the impact of previous surgery and tumor volume on extent of resection and recurrence as well as the method of closure on rate of CSF leak.

RESULTS

Between January 2009 and February 2017, 7 patients (4 males and 3 females; age range 16-70 years) underwent a total of 8 surgeries for EC resection utilizing the EEA. Transplanum and transclival extensions were performed in 3 and 5 patients, respectively. Methods of closure incorporated a gasket seal in 6 of 8 procedures and a nasoseptal flap in 7 of 8 procedures. Gross-total resection (GTR) was achieved in 43% of patients, and near-total resection (> 95%) was obtained in another 43%. Complications included diabetes insipidus (n = 2), postoperative CSF leak (n = 2), transient third cranial nerve palsy (n = 1), and epistaxis (n = 1). With a mean follow-up of 43.5 months, recurrence has been observed in 2 of 7 patients. In 1 case, reoperation for recurrence was required 71 months following the initial surgery. Use of the gasket-seal technique with nasoseptal flap coverage significantly correlated with the absence of postoperative CSF leakage (p = 0.018). GTR was achieved in 25% of the patients who had prior surgeries and in 50% of patients without previous resections. The mean volume of cysts in which GTR was achieved (4.3 ± 1.8 cm3) was smaller than that in which subtotal or near-total resection was achieved (12.2 ± 11 cm3, p = 0.134).

CONCLUSIONS

The EEA for resection of ECs of the ventral cranial base is a safe and effective operative strategy that avoids crossing the plane of the cranial nerves. In the authors' experience, gasket-seal closure with nasoseptal flap coverage has been associated with a decreased risk of postoperative CSF leakage.

Nonvestibular Schwannoma Tumors in the Cerebellopontine Angle: A Single-Surgeon Experience

Background:

The most common cerebellopontine angle (CPA) tumor is a vestibular schwannoma. Schwannomas account for 8.5% of all intracranial tumors and more than 90% of the tumors originate from the eighth cranial nerve, but one in five CPA tumors are not vestibular schwannoma. These tumors may have different manifestations and require different management strategies.

Methods:

We report 224 consecutive NVCPAT operated in the Department of Neurosurgery, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, by the senior author between 2001 and 2014 and discuss the different approaches and outcomes in NVCPAT.

Results:

The age range was 20–60 years and there were 129 females and 95 male patients. The clinical material consisted of 81 cases of meningioma (36.1%), 44 cases of epidermoid (19.64%), 34 cases of trigeminal schwannoma (15.17%), 26 cases of jugular foramen schwannoma (11.60%), and 39 cases of other tumors (17.41%). In nonvestibular schwannoma (NVS), symptoms and signs from cranial nerve VIII are less frequent and other cranial nerves and cerebellar symptoms and signs predominate.

Conclusion:

Symptoms and signs are different in NVCPAT from those found in patients with vestibular schwannoma. Hearing loss is not the predominant symptoms. Cerebellar signs and trigeminal dysfunction are more common. The most common approach used in the current series was retrosigmoid craniotomy. Gamma knife radiosurgery was a useful adjunct in a subset of these patients.

Endoscopic endonasal surgery for epidermoid and dermoid cysts: a 10-year experience

OBJECTIVE

Epidermoid and dermoid cysts may be found along the cranial base and are commonly resected via open transcranial approaches. The use of endoscopic endonasal approaches for resection of these tumors has been rarely reported.

METHODS

The authors retrospectively reviewed the medical records of 21 patients who underwent endoscopic endonasal surgery for epidermoid and dermoid cyst resection at the University of Pittsburgh Medical Center between January 2005 and June 2014. Surgical outcomes and variables that might affect the extent of resection and complications were analyzed.

RESULTS

Total resection (total removal of cyst contents and capsule) was achieved in 8 patients (38.1%), near-total resection (total removal of cyst contents, incomplete removal of cyst capsule) in 9 patients (42.9%), and subtotal resection (incomplete removal of cyst contents and capsule) in 4 patients (19%). Larger cyst volume (≥ 3 cm3) and intradural location (15 cysts) were significantly associated with nontotal resection (p = 0.008 and 0.0005, respectively). In the whole series, surgical complications were seen in 6 patients (28.6%). No complications were observed in patients with extradural cysts. Among the 15 patients with intradural cysts, the most common surgical complication was postoperative CSF leak (5 patients, 33.3%), followed by postoperative intracranial infection (4 patients, 26.7%). Larger cysts and postoperative CSF leak were associated with intracranial infection (p = 0.012 and 0.028, respectively). Subtotal resection was marginally associated with intracranial infection when compared with total resection (p = 0.091). All patients with neurological symptoms improved postoperatively with the exception of 1 patient with unchanged abducens nerve palsy.

CONCLUSIONS

Endoscopic endonasal approaches may be effectively used for resection of epidermoid and dermoid cysts in carefully selected cases. These approaches are recommended for cases in which a total or near-total resection is possible in addition to a multilayer cranial base reconstruction with vascularized tissue to minimize the risk of intracranial infection.

[Anatomical rationale for surgical treatment of trigeminal neuralgia combined with cerebellopontine angle tumors]

Trigeminal neuralgia (TN) can be combined with tumors of the cerebellopontine angle (CPA). The optimal surgical management in these cases depends on the anatomical relationship of the trigeminal nerve root (TNR) with tumors and vessels. The purpose of this study is to evaluate variants of the anatomical relationship between the TNR and the surrounding structures as well as to analyze the results of using various surgical techniques for treatment of TN in CPA tumors.

MATERIAL AND METHODS

We performed a retrospective analysis of 51 patients (38 females and 13 males aged 22 to 77 years) with TN and ipsilateral CPA tumors. Space-occupying lesions were represented by 29 meningiomas of the petrous apex, 11 epidermoids, 9 vestibular schwannomas, 1 hemangioma, and 1 cavernoma.

RESULTS

Intraoperatively, we identified 6 types of the anatomical relationships among the TNR, tumors, and CPA vessels: type I - the TNR is completely surrounded by the tumor (4 epidermoids); type II - the tumor compresses and displaces the TNR (21 meningiomas, 4 schwannomas, and 6 epidermoids); type III - the tumor occurs inside the TNR (1 cavernoma); type IV - the tumor together with the vessel compresses the TNR (3 meningiomas and 1 epidermoid); type V - the tumor displaces the TNR towards the vessel (5 meningiomas and 5 schwannomas); type VI - the tumor does not contact the TNR that is compressed by the vessel (1 hemangioma). Preoperative MRI and intraoperative findings revealed compression and deformity of the brain stem at the TNR entry level in all but two patients. Vascular compression of the TNR (usually by the superior cerebellar artery) was found in 15 of 51 patients. Microvascular decompression (MVD) was performed using various techniques: interposition of implants between vessels and the TNR, transposition of the compressing vessels from the TNR, or transposition of the nerve root. In all patients, except 1, pain syndrome regressed immediately after tumor removal and MVD. In 1 case, the pain syndrome did not regress after total removal of epidermoid and MVD, and TN was resolved by percutaneous radiofrequency rhizotomy. Long-term postoperative follow-up results showed complete elimination of TN in all cases; there were no persistent neurological complications and postoperative mortality.

CONCLUSION

TN may result from direct compression and deformation of the TNR and brain stem by CPA tumors. In some cases, the cause of TN is combined compression of the TNR by the tumor and vessels. Assessment of the neurovascular relationships requires detailed examination of the entire TNR after tumor removal. In the case of vascular compression of the TNR, various MVD techniques can be used for treatment of TN.

Executive Dysfunction After Fourth-Ventricle Epidermoid Cyst Resection

Intracranial epidermoid cysts are rare, comprising 0.2% to 1.8% of all primary intracranial expanding lesions, of which <5% occur within the fourth ventricle. Epidermoid cysts are frequently congenital, and patients often present in the fourth decade of life. These cysts produce symptoms as a result of mass effect on surrounding structures, most commonly the cerebellum and cranial nerves. Symptoms can include hearing impairment, trigeminal neuralgia (severe facial pain), facial tics, headaches, double vision, and facial palsy. However, no research has focused on the neuropsychological effects on a patient after surgical resection of these cysts. This case report presents the cognitive profile of a woman after resection of an epidermoid cyst in the fourth ventricle. The 49-year-old patient underwent neuropsychological assessment after removal of the cyst, completing a comprehensive set of cognitive tests of estimated premorbid intelligence, attention, memory, social cognition, language, visual perception, and executive functioning. Test results indicated executive dysfunction and reduced visuospatial memory in the acute stage after surgical removal of the epidermoid cyst. These findings suggest that cognitive deficits can occur after resection of space-occupying lesions in brain regions not typically associated with cognition. To our knowledge, this is the first report of the neuropsychological consequences of surgical removal of a congenital epidermoid cyst in the fourth ventricle. An understanding of the neuropsychological sequelae of this rare cerebral cyst will allow patients, families, and health professionals to better anticipate and manage postoperative difficulties.

Surgical Management of Intracranial Giant Epidermoid Cysts in Adult: A Case-Based Update

Epidermoid cysts (ECs) are benign and slow-growing lesions that account for about 0.2%-2% of all intracranial tumors. Symptoms appear slowly and tumors may have already grown to giant proportions when patients receive their first diagnosis. The optimal treatment for ECs is surgical removal, which includes the total resection of the entire capsule of the lesion in order to minimize the risk of malignant transformation associated with partial removal. However, considering the giant size that the ECs can reach at the time of the diagnosis, and their adherence to the surrounding structures, the risks and benefits of total versus subtotal resections in the short- and long-term patients' outcome are still under debate. Here, we report a case of an extensive giant EC and offer a discussion of its characteristics, surgical management, and postoperative outcome, taking a cue to argue about the recent literature based in the latest case studies.

Cranial Nerve Preservation Following Surgical Treatment for Epidermoid Cysts of the Posterior and Middle Fossae

Epidermoid cysts are rare lesions, accounting for 0.2 to 1.8% of all intracranial tumors. They most commonly occur in the cerebellopontine angle where they may cause a breadth of neurologic complications due to mass effect on the nearby cranial nerves (CN), vascular structures, and the brain stem. Treatment of epidermoid cysts is surgical, with the goal of complete resection using microsurgical technique and even more importantly preservation of the involved CNs, vasculature, and brain parenchyma. Successful surgery can result in total resolution of symptoms, but, in certain situations, may not be advisable due to adherence, scarring, or inflammation making dissection of CN fascicles difficult and possibly hazardous. We conducted a retrospective review from 1998 to 2016 and compiled a series of 28 skull base epidermoid cysts operated on at our institution. Cases were evaluated for presenting symptoms, history of prior resection, and postoperative results including CN function, extent of resection, residual tumor, and need for reoperations. The average tumor size (largest diameter) was 3.9 cm with a range of 1 to 7cm. Eighteen of twenty-eight (64%) patients underwent a gross total resection and ten underwent subtotal resection. No patients, whether presenting with CN deficits or not, experienced permanent worsening of CN function following surgery. Complete resection of epidermoid cysts should remain a high priority of therapy, but, in our opinion, preservation of CN function should be a primary goal, determining the extent of resection to provide patients with the highest quality of life possible following surgery.

Suprasellar Epidermoid Cyst Originating from the Infundibulum: Case Report and Literature Review

Epidermoid cysts account for a small fraction of intracranial brain tumors, most commonly found in the cerebellopontine angle and parasellar cisterns. Here we present a rare case of an epidermoid cyst located in the suprasellar region, specifically originating from the infundibulum. Only one additional case with an epidermoid cyst originating within the pituitary stalk has been previously reported in the literature. The patient in this case presented with headaches, diplopia and blurred vision without any endocrinopathy. The patient's pre-operative evaluation was significant for pseudotumor cerebri, hyponatremia, obesity, and a history of smoking; post-operative course was significant for neurogenic diabetes insipidus.

Minimally invasive endoscopic-assisted approaches to the posterior fossa

Modern surgical approaches are becoming more minimalistic, associated with the term "minimally invasive." The endoscope provides a more panoramic anatomical view in addition to the ability to access narrow deep corners with decent illumination and clear visualization. Endoscopic assisted microsurgery through a tailored small craniotomy is the foundation of keyhole surgery. The endoscope can be advanced deeper into the field, thus enhancing an exposure and allowing bimanual dissection, ultimately providing smaller craniotomies and tailored key exposures. The term "minimally invasive" became associated with reduction of overall tissue injury, decreased potential complications, reduced recovery times/hospital stay, and overall reduced costs. This minimally invasive concept became successfully applicable to diverse pathologies in the three cranial fossae. The posterior fossa houses the most critical neurovascular structures of the brain in an intricate and complex anatomical organization. In this manuscript, we describe keyhole endoscopic-assisted approaches to different regions of the posterior fossa. Five corridors for these approaches are described: 1) midline supracerebellar-infratentorial to the pineal region; 2) upper cerebellopontine angle (CPA) to the trigeminal region; 3) middle cerebellopontine angle to the vestibulocochlear region and internal auditory meatus; 4) inferior cerebellopontine angle to the jugular foramen region and lower cranial nerves; and 5) midline infracerebellar to posterior foramen magnum and the craniocervical junction. We then present a general review of the published literature and case examples demonstrating the effectiveness of the endoscopic-assisted keyhole concept.

Combined microsurgical and endoscopic technique for removal of extensive intracranial epidermoids

Background

Intracranial epidermoid tumors are challenging lesions because they grow along the subarachnoid spaces around delicate neurovascular structures and often extend from one compartment to another. The purpose of this study was to determine the usefulness of endoscopic assistance in the microsurgical resection of these lesions, in which total resection is therapy of choice.

Methods

A total of 48 cases of intracranial epidermoids were treated by combined microscopic and endoscopic techniques. Initially, the tumor was removed under the microscope and after ensuring maximum excision, the endoscope was used to find out and excise any residual tumor.

Results

Out of these 48 cases complete excision was achieved in 44 cases and subtotal excision in four patients. Postoperative complications were seen in 17 patients, but none of the complications was attributed to the use of endoscope. Overall use of endoscope benefited 79% of cases.

Conclusion

We recommend combined microsurgical and endoscopic approach to achieve complete/maximum resection of extensive intracranial epidermoid tumors.

Cerebellar Vermian Epidermoid Tumor: A Report of 2 Cases

BACKGROUND

Epidermoid tumors are rare, benign slow-growing congenital tumors, most frequently located in the cerebellopontine angle of the intracranial cavity. They usually grow to a large size before patients become symptomatic. Although these tumors are amenable to surgery, their adherence to neurovascular structures poses a surgical challenge that results in subtotal resection, thus increasing the risk of recurrence.

CASE DESCRIPTION

We report 2 adult patients whose imaging studies revealed epidermoid tumors located in the cerebellar vermis, an uncommon site for such tumors. The patients presented with variable symptomatology. We highlight the imaging features and challenges of surgery. Both patients had good outcomes, with resolution of symptoms and neurologic deficits.

CONCLUSIONS

A safe complete excision of epidermoid tumor and its capsule is possible with a good understanding of their clinical and radiologic features and a high index of suspicion. To the best of our knowledge, this is the first report of cerebellar vermian epidermoid tumors from sub-Saharan Africa.

The Xomed Monopolar Cranial Nerve Stimulator Electrode: A Surprising Handy Tool for Deep Dissection of Epidermoid Tumors

Epidermoid cysts are notorious for their propensity to sneak into deep recesses between cranial nerves in the posterior fossa. Attempts to achieve complete excision using ordinary instruments when tempted by the seeming ease of dissection is known to cause unacceptable deficits. The Xomed monopolar stimulator electrode probe of the nerve integrity electromyography monitor has several advantages when used as the primary dissection tool for deep-seated epidermoid cysts. Cerebellopontine angle epidermoid is the classical prototype of a strategically placed deep-seated epidermoid tumor.

The author describes the use of the monopolar stimulator electrode of the nerve integrity electromyography monitor as the primary dissection tool for excising epidermoid cysts of the cerebellopontine angle. Thin profile, rounded nontraumatic tip, and springiness of the body of the monopolar electrode aid the dissection.

The monopolar electrode was used to tease and scoop out the flakes aided by a fine suction. An initial internal decompression allowed the capsule to be folded away and separated from neurovascular structures using the dissector. The thin profile of both the instruments allowed good visualization and delicate control over the dissection in depths of the resection cavity without undue traction or impacts on superficially dissected cranial nerves. This novel use of the monopolar electrode was employed in the surgical excision of epidermoid cysts of the cerebellopontine angle in nine patients.

Total or near total excision was possible in eight of the nine patients who underwent excision using this technique. In three patients, mild deficits primarily of the fifth nerve sensory function were noted.

The Xomed monopolar stimulating electrode of the nerve integrity electromyography monitor is an ideal instrument for deep dissection of epidermoid cysts in areas where neurovascular structures are at risk.

Epidermoid cysts of the cavernous sinus: clinical features, surgical outcomes, and literature review

OBJECTIVE

Epidermoid cysts of the cavernous sinus (CS) are rare, and no large case series of these lesions has been reported. In this study, the authors retrospectively reviewed the outcomes of the surgical management of CS epidermoid cysts undertaken at their center and performed a review of any such cysts reported in the literature over the past 40 years.

METHODS

Clinical data were obtained on 31 patients with CS epidermoid cysts that had been surgically treated at the authors' hospital between 2001 and 2016. The patients' medical records, imaging data, and follow-up outcomes were retrospectively analyzed. The related literature from the past 40 years (18 articles, 20 patients) was also evaluated.

RESULTS

The most common chief complaints were facial numbness or hypesthesia (64.5%), absent corneal reflex (45.2%), and abducens or oculomotor nerve deficit (35.5%). On MRI, 51.6% of the epidermoid cysts showed low T1 signals and equal or high T2 signals. In the other lesions, the radiological findings varied considerably given differences in the composition of the cysts. Surgery was performed via the extradural approach (58.1%), intradural approach (32.3%), or a combined approach (9.7%). After the operation, symptoms remained similar or improved in 90.3% of patients and new oculomotor paralysis developed after the operation in 9.7% of patients. Seven patients (22.6%) developed meningitis postoperatively (5 aseptic and 2 septic), and all of them recovered. All patients achieved good recovery before discharge (Karnofsky Performance Status score ≥ 70). Over an average follow-up of 4.6 ± 3.0 years in 25 patients (80.6%), no recurrence or reoperation occurred, regardless of whether total or subtotal resection of the capsule had been achieved.

CONCLUSIONS

Both the extradural and intradural approaches can enable satisfactory lesion resection. A favorable prognosis and symptomatic improvement can be expected after both total and subtotal capsule resections. Total capsule resection is encouraged to minimize the possibility of recurrence provided that the resection can be safely performed.

Gamma knife radiosurgery for cerebellopontine angle epidermoid tumors

Background:

Intracranial epidermoid tumors are commonly found in the cerebellopontine angle where they usually present with either trigeminal neuralgia or hemifacial spasm. Radiosurgery for these tumors has rarely been reported. The purpose of this study is to assess the safety and clinical outcome of the treatment of cerebellopontine epidermoid tumors with gamma knife radiosurgery.

Methods:

This is a retrospective study involving 12 patients harboring cerebellopontine angle epidermoid tumors who underwent 15 sessions of gamma knife radiosurgery. Trigeminal pain was present in 8 patients and hemifacial spasm in 3 patients. All cases with trigeminal pain were receiving medication and still uncontrolled. One patient with hemifacial spasm was medically controlled before gamma knife and the other two were not. Two patients had undergone surgical resection prior to gamma knife treatment. The median prescription dose was 11 Gy (10–11 Gy). The tumor volumes ranged from 3.7 to 23.9 cc (median 10.5 cc).

Results:

The median radiological follow up was 2 years (1–5 years). All tumors were controlled and one tumor shrank. The median clinical follow-up was 5 years. The trigeminal pain improved or disappeared in 5 patients, and of these, 4 cases stopped their medication and one decreased it. The hemifacial spasm resolved in 2 patients who were able to stop their medication. Facial palsy developed in 1 patient and improved with conservative treatment. Transient diplopia was also reported in 2 cases.

Conclusion:

Gamma knife radiosurgery provides good clinical control for cerebellopontine angle epidermoid tumors.

Primary Epidermoid Tumors of the Cerebellopontine Angle: A Review of 47 Cases

OBJECTIVE

To analyze disease presentation, treatment, and clinical course of a consecutive series of patients with primary cerebellopontine angle (CPA) epidermoids.

PATIENTS

Forty-seven consecutive patients with previously untreated CPA epidermoids.

INTERVENTION(S)

Observation and microsurgery.

MAIN OUTCOME MEASURES

Disease- and treatment-associated morbidity, recurrence.

RESULTS

Forty-seven patients (mean age 39 years; 53% women) were analyzed and the average duration of follow-up was 42 months. The most common presenting symptom was headache (27; 57%); 13 (28%) exhibited preoperative asymmetric sensorineural hearing loss, 3 (6%) facial nerve paresis, and 3 (6%) hemifacial spasm. Thirteen patients (28%) were initially observed over a mean interval of 56 months; however, five experienced disease progression requiring operation. Thirty-nine patients (83%) underwent surgical resection; 18 (46%) received gross total, 5 (13%) near total, and 16 (41%) aggressive subtotal resection. Three patients (8%) recurred at a median of 53 months; two after subtotal and one after gross total resection. Ninety-three percent of patients with useful hearing maintained serviceable hearing following treatment and one patient (3%) experienced mild long-term postoperative facial nerve paresis (HB II/VI). All patients with preoperative facial nerve paresis recovered normal function postoperatively. There were no episodes of stroke or death.

CONCLUSIONS

Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression from CPA epidermoids. Gross total resection is preferred; however, aggressive subtotal removal should be considered with adherent or extensive disease as reoperation rates are low, even in the setting of aggressive subtotal resection. Conservative observation with serial imaging is a viable initial strategy in asymptomatic or minimally symptomatic patients.

Surgical Resection of Cerebellopontine Epidermoid Cysts: Limitations and Outcome

Objective  Epidermoid cysts are benign slowly growing tumors commonly involving the cerebellopontine angle (CPA). The aim of this study was to analyze the surgical limitations, surgical strategies, complications, and outcome of resection of these lesions. Material and Methods  The clinical data and outcome of 32 cases operated for CPA epidermoid between 2007 and 2015 were retrospectively analyzed. The mean follow-up period was 42.6 months, and all patients were followed up at least for a whole year. Results  There were 15 males and 17 females. The median age was 37.6 years. Headache and cranial nerves dysfunction were the most common presenting symptoms. Surgery was performed in all patients using the standard lateral suboccipital retrosigmoid approach. In three cases, microvascular decompression of an arterial loop was performed in addition to tumor excision. Total resection was accomplished in 19 out of 32 cases (59.4%), subtotal resection in 7 cases (21.9%), and only partial excision was achieved in 6 cases (18.7%). There was no recurrence or regrowth of residual tumor during the follow-up period. We had a single postoperative mortality due to postoperative pneumonia and septic shock. New cranial nerves deficits occurred in 15.6% of cases but were transient in most of them. Conclusion  The favorable outcome of total resection of CPA epidermoids should always be weighed against the critical risks that accompany it especially in the presence of tight adhesions to vital neurovascular structures. The retrosigmoid approach is suitable for the resection of these tumors even if they were large in size.

Brainstem epidermoid cyst: An update

The incidence of epidermoid tumors is between 1% and 2% of all intracranial tumors. The usual locations of epidermoid tumor are the parasellar region and cerebellopontine angle, and it is less commonly located in sylvian fissure, suprasellar region, cerebral and cerebellar hemispheres, and lateral and fourth ventricles. Epidermoid cysts located in the posterior fossa usually arise in the lateral subarachnoid cisterns, and those located in the brain stem are rare. These epidermoids contain cheesy and flaky white soft putty like contents. Epidermoid cysts are very slow growing tumors having a similar growth pattern of the epidermal cells of the skin and develop from remnants of epidermal elements during closure of the neural groove and disjunction of the surface ectoderm with neural ectoderm between the third and fifth weeks of embryonic life. We are presenting an interesting case of intrinsic brainstem epidermoid cyst containing milky white liquefied material with flakes in a 5-year-old girl. Diffusion-weighted imaging is definitive for the diagnosis. Ideal treatment of choice is removal of cystic components with complete resection of capsule. Although radical resection will prevent recurrence, in view of very thin firmly adherent capsule to brainstem, it is not always possible to do complete resection of capsule without any neurological deficits.

Cyst-cisternal shunting for cystic multirecurrent brainstem epidermoid: case report and literature review

BACKGROUND

Surgical treatment of recurrent, posterior cranial fossa epidermoids in multioperated patients carries significant morbidity, mainly due to tumor adhesion to cranial nerves and vessels, and brainstem involvement. Radical resection is often not feasible; therefore surgery should aim to restore cerebrospinal fluid circulation, release engulfed neurovascular structures, and relieve brainstem compression. Intra-axial epidermoids are extremely rare. We present an innovative surgical technique of a cyst-cisternal shunting to treat cystic recurrent, unresectable brainstem epidermoids.

METHODS

The surgical technique is stepwise described and a case illustration is reported. The pertinent literature has been reviewed.

RESULTS

Few cases of brain stem epidermoid tumors have been described to date. The surgical steps of this technique and related intraoperative images are provided. One case illustration regarding the resection of a large recurrent cystic intra-axial brainstem epidermoid is reported to demonstrate the application of the technique in a clinical setting. The patient was followed up for 14 years and did not experience any recurrence, showing a stable disease at the last follow-up control. A systematic review of the competent literature has been provided.

CONCLUSIONS

Cyst-cisternal shunting in case of recurrent, brainstem epidermoid is a safe and long-term effective technique to relieve mass effect into the brainstem.

Treatment of epidermoid tumors with gamma knife radiosurgery: Case series

Background:

Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery.

Case Description:

Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery.

Conclusion:

Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs.

Cerebellopontine angle epidermoid cysts: clinical presentations and surgical outcome

Epidermoid cysts constitute less than 1% of intracranial tumors with the majority of them involving cerebellopontine angle (CPA). Although several mechanisms for cranial nerve dysfunction due to these tumors have been proposed, no direct evaluation for hyper- or hypoactive dysfunction has been done. In this case series, pathophysiology of cranial nerve dysfunction in CPA epidermoid cysts was evaluated with special attention to a new mechanism of capsule strangulation caused by stratified tumor capsule. Twenty-two cases with epidermoid cysts of CPA micro-neurosurgically treated in our departments since 2005 were reviewed. Clinical status of the patients before the surgery and post-operative functional outcome were recorded. Available data from the English literature were summarized for comparison. Mass reduction of cyst contents in most cases was usually associated with prompt and marked improvement of the symptoms suggesting neuroapraxia caused by compression of the tumor content and/or mild ischemia. Among them, two cases showed strangulation of the affected nerves by the tumor capsule whose preoperative dysfunction did not improve after surgery in spite of meticulous microsurgical removal of the lesion. Involved facial and abducent nerves in these two cases showed distortion of nerve axis and nerve atrophy distal to the strangulation site. We report the first direct evidence of etiology of cranial nerve dysfunction caused by cerebellopontine angle epidermoid tumors. Young age and rapidly progressive neurological deficit might be the characteristics for strangulation of the affected nerves by the cyst capsule. Even though the number of cases might be limited, immediate decompression and release of the strangulating band might be urged in such patients to prevent irreversible deficits.

Ruptured pediatric cerebellopontine angle epidermoid cyst: a case report detailing radiographic evolution and clinical course

Epidermoid cysts (ECs) are uncommon pediatric tumors that often occur in the cerebellopontine angle. Although cyst rupture is a recognized complication, the radiographic evolution of an EC following rupture and the resultant parenchymal brainstem edema have not been reported. The authors present the case of a 13-year-old female with a newly diagnosed cerebellopontine angle EC who presented with worsening headaches, photophobia, and emesis. Magnetic resonance imaging demonstrated significant pericystic brainstem edema and mass effect with effacement of the fourth ventricle. Refractory symptoms prompted repeat imaging, revealing cyst enlargement and dense rim enhancement. Resection of the EC resolved both her symptoms and the brainstem edema. This case documents the radiographic evolution of EC rupture and subsequent clinical course.

Giant intracranial epidermoids: is total removal feasible?

OBJECT

Epidermoid tumors arise from misplaced squamous epithelium and enlarge through the accumulation of desquamated cell debris. Optimal treatment consists of total removal of the capsule; therefore, giant and multicompartmental tumors are particularly challenging. A conservative attitude in handling the tumor capsule is common given concerns about capsule adherence to neurovascular structures, and thus the possibility of recurrence is accepted with the intent of minimizing complications. This study focuses on the outcome of surgery in patients with giant epidermoid tumors for which total capsule removal was the aim.

METHODS

The authors conducted a retrospective analysis of all patients with giant epidermoid tumors treated by the senior author (O.A.), who pursued total removal of the capsule through skull base approaches. Patients were divided into 2 groups: one including patients with de novo tumors and the other consisting of patients who presented with recurrent tumors.

RESULTS

Thirty-four patients had undergone 46 operations, and the senior author performed 38 of these operations in the study period. The average tumor dimensions were 55 × 36 mm, and 25 tumors had multicompartmental extensions. Total removal of the tumor and capsule was achieved with the aid of the microscope in 73% of the 26 de novo cases but in only 17% of the 12 recurrent tumor cases. The average follow-up among all patients was 111 months (range 10–480 months), and the average postsurgical follow-up was 56.8 months (range 6–137 months). There were 4 recurrences in the de novo group, and every case had had a small piece of tumor capsule left behind. One patient died after delayed rupture of a pseudoaneurysm. In the de novo group, the average preoperative Karnofsky Performance Scale (KPS) score was 71.42%, which improved to 87.14% on long-term follow-up. In the group with recurrences, the KPS score also improved on long-term follow-up, from 64.54% to 84.54%. In the de novo group, 3 cases (11.5%) had permanent cranial nerve deficits, and 4 cases (15.4%) had a CSF leak. In the recurrence group, 3 cases (25%) had new, permanent cranial nerve deficits, and 1 (8.3%) had a CSF leak. Two patients in this group developed hydrocephalus and required a shunt.

CONCLUSIONS

Total removal of the capsule of giant epidermoid tumors was achieved in 73% of patients with de novo tumors and was associated with improved function, low morbidity and mortality, and a lower risk of recurrence. Surgery in patients with recurrent tumors was associated with higher morbidity and persistence of the disease.