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

Hearing Preservation and Functional Outcomes After Resection of Epidermoid Lesions of the Cerebellopontine Angle With High Hearing Risk

OBJECTIVES

To assess a decade of experience of treating patients with high hearing risk cerebellopontine angle (CPA) epidermoid lesions and examine factors influencing postoperative outcomes, particularly hearing preservation.

STUDY DESIGN

Retrospective chart review.

SETTING

Single tertiary-referral center.

PATIENTS

Adults with CPA epidermoid lesions who presented with hearing loss or evidence of lesion involving vestibulocochlear nerve.

INTERVENTIONS

The studied intervention was microsurgical resection.

MAIN OUTCOME MEASURES

Main outcome measures included extent of resection, hearing preservation rate for patients with postoperative audiograms, and disease progression.

RESULTS

Twenty-three adults with an average tumor volume of 15.63 ± 16.2 cm3 were included. Five lesions (22%) involved the full internal auditory canal (IAC), 11 (48%) had partial involvement, and 5 (22%) were IAC sparing. Most patients with IAC involvement (88%) had circumferential invasion of the canal. Patients underwent either a retrosigmoid (18, 79%) or combined retrolabyrinthine transpetrosal approach (5, 22%), and gross total resection was achieved in most cases (13, 57%). Of 12 patients with postoperative audiograms, 10 (83%) had preoperative hearing preserved. There was no statistically significant change in hearing scores with treatment based on preoperative extent of IAC involvement. Ten patients (43%) had residual lesions postoperatively, and 6 exhibited progression. One patient ultimately required reoperation 6 years after initial surgery.

CONCLUSIONS

Preoperative hearing was preserved in the majority of the patients who underwent resection of CPA epidermoids via a retrosigmoid or transpetrosal approach. CPA epidermoids often invaded the IAC; however, degree of invasion was not associated with hearing outcomes.

Tumors of the nervous system and hearing loss: Beyond vestibular schwannomas

Hearing loss is a common side effect of many tumor treatments. However, hearing loss can also occur as a direct result of certain tumors of the nervous system, the most common of which are the vestibular schwannomas (VS). These tumors arise from Schwann cells of the vestibulocochlear nerve and their main cause is the loss of function of NF2, with 95 % of cases being sporadic and 5 % being part of the rare neurofibromatosis type 2 (NF2)-related Schwannomatosis. Genetic variations in NF2 do not fully explain the clinical heterogeneity of VS, and interactions between Schwann cells and their microenvironment appear to be critical for tumor development. Preclinical in vitro and in vivo models of VS are needed to develop prognostic biomarkers and targeted therapies. In addition to VS, other tumors can affect hearing. Meningiomas and other masses in the cerebellopontine angle can compress the vestibulocochlear nerve due to their anatomic proximity. Gliomas can disrupt several neurological functions, including hearing; in fact, glioblastoma multiforme, the most aggressive subtype, may exhibit early symptoms of auditory alterations. Besides, treatments for high-grade tumors, including chemotherapy or radiotherapy, as well as incomplete resections, can induce long-term auditory dysfunction. Because hearing loss can have an irreversible and dramatic impact on quality of life, it should be considered in the clinical management plan of patients with tumors, and monitored throughout the course of the disease.

Balloon compression, neuroendoscopy and electrophysiological monitoring-assisted retrosigmoid approach for resection of cholesteatoma in the cerebellopontine angle-Meckel's cave: a technical description

We report a case of cholesteatoma that caused left facial pain with facial numbness. The tumour was located in the left cerebellopontine angle (CPA) and Meckel's cave. A balloon was first placed into Meckel's cave, and then, under electrophysiological monitoring, the tumour within the CPA cistern was resected via the retrosigmoid approach. The balloon was inflated in Meckel's cave to push the tumour out of Meckel's cave, and then, the tumour was completely removed under endoscopy. The symptoms, including pain and numbness, subsided after surgery.

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.

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.

Extent of resection of epidermoid tumors and risk of recurrence: case report and meta-analysis

OBJECTIVE

Intracranial epidermoid tumors are slow-growing, histologically benign tumors of epithelial cellular origin that can be symptomatic because of their size and mass effect. Neurosurgical resection, while the treatment of choice, can be quite challenging due to locations where these lesions commonly occur and their association with critical neurovascular structures. As such, subtotal resection (STR) rather than gross-total resection (GTR) can often be performed, rendering residual and recurrent tumor potentially problematic. The authors present a case of a 28-year-old man who underwent STR followed by aggressive repeat resection for regrowth, and they report the results of the largest meta-analysis to date of epidermoid tumors to compare recurrence rates for STR and GTR.

METHODS

The authors conducted a systemic review of PubMed, Web of Science, and the Cochrane Collaboration following the PRISMA guidelines. They then conducted a proportional meta-analysis to compare the pooled recurrence rates between STR and GTR in the included studies. The authors developed fixed- and mixed-effect models to estimate the pooled proportions of recurrence among patients undergoing STR or GTR. They also investigated the relationship between recurrence rate and follow-up time in the previous studies using linear regression and natural cubic spline models.

RESULTS

Overall, 27 studies with 691 patients met the inclusion criteria; of these, 293 (42%) underwent STR and 398 (58%) received GTR. The average recurrence rate for all procedures was 11%. The proportional meta-analysis showed that the pooled recurrence rate after STR (21%) was 7 times greater than the rate after GTR (3%). The average recurrence rate for studies with longer follow-up durations (≥ 4.4 years) (17.4%) was significantly higher than the average recurrence rate for studies with shorter follow-up durations (< 4.4 years) (5.7%). The cutoff point of 4.4 years was selected based on the significant relationship between the recurrence rate of both STR and GTR and follow-up durations in the included studies (p = 0.008).

CONCLUSIONS

STR is associated with a significantly higher rate of epidermoid tumor recurrence compared to GTR. Attempts at GTR should be made during the initial surgery with efforts to optimize success. Surgical expertise, as well as the use of adjuncts, such as intraoperative MRI and neuromonitoring, may increase the likelihood of completing a safe GTR and decreasing the long-term risk of recurrence. The most common surgical complications were transient cranial nerve palsies, occurring equally in STR and GTR cases when reported. In all postoperative epidermoid tumor cases, but particularly following STR, close follow-up with serial MRI, even years after surgery, is recommended.

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.

Clinical Features and Surgical Management of Cerebellopontine Angle Cholesteatoma That Presented as Trigeminal Neuralgia

BACKGROUND

It is difficult to differentiate patients with cerebellopontine angle (CPA) cholesteatoma and patients with primary trigeminal neuralgia just according to early symptoms. We aimed to explore the clinical characteristics, early diagnosis, and microneurosurgical techniques for CPA cholesteatoma that presented as trigeminal neuralgia.

METHODS

The data of 26 patients who complained trigeminal neuralgia with CPA cholesteatoma between January 2009 and December 2015 were collected and studied retrospectively, they were diagnosed by magnetic resonance imaging preoperatively and confirmed by pathology postoperatively. All the tumors were resected through a retrosigmoidal approach. In 26 cases, 14 patients who underwent cholesteatoma resection and microvascular decompression were assigned to group A and 12 patients who underwent only cholesteatoma resection were assigned to group B. The clinical features and surgical results between groups A and B were compared. The complications and surgical results were followed up, and surgical techniques were summarized.

RESULTS

All patients presented as trigeminal neuralgia at the same side of the cholesteatoma. There was no statistical difference between the 2 groups in clinical features and surgical results between groups A and B. All patients with cholesteatoma showed clear and significant imaging characteristics. The tumors were totally removed in 18 patients and subtotally removed in 8 patients. Pain relief was satisfactory in all patients. Surgical complications included transient aseptic meningitis in 2 patients, facial numbness in 2 patients, mild tinnitus in 2 patients, mild and facial weakness in 1 patient. No death, hematoma, or acute hydrocephalus were reported in this series. During the follow-up of 12-80 months, no patient experienced recurrence of pain or tumor.

CONCLUSIONS

Cholesteatoma of the cerebellopontine angle often presented as trigeminal neuralgia. Magnetic resonance imaging is helpful for early diagnosis according to its distinct signal. Surgical treatment is often the first choice, the neuralgia relief was satisfactory after operation. Microvascular decompression is recommended simultaneously if some offending vessels were founded during the surgical resection of the tumor.

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.