Large Cystic Vestibular Schwannoma Research Articles

Long-term results of upfront, single-session Gamma Knife radiosurgery for large cystic vestibular schwannomas.

Anecdotally, cystic vestibular schwannomas (cVSs) are regarded to have unpredictable biologic activity with poorer clinical results, and most studies showed a less favorable prognosis following surgery. While stereotactic radiosurgery (SRS) is a well-established therapeutic option for small- to medium-sized VSs, cVSs are often larger, thus making upfront SRS more complicated. The purpose of this retrospective study was to assess the efficacy and safety of upfront SRS for large cVSs. The authors reviewed the data of 54 patients who received upfront, single-session Gamma Knife radiosurgery (GKRS) with a diagnosis of large cVS (> 4 cm3). Patients with neurofibromatosis type 2, multiple VSs, or recurrent VSs and < 24months of clinical and neuroimaging follow-up were excluded. Hearing loss (48.1%) was the primary presenting symptom. The majority of cVSs were Koos grade IV (66.7%), and the most prevalent cyst pattern was "mixed pattern of small and big cysts" (46.3%). The median time between diagnosis and GKRS was 12months (range, 1-147months). At GKRS, the median cVS volume was 6.95 cm3 (range, 4.1-22 cm3). The median marginal dose was 12Gy (range, 10-12Gy). The mean radiological and clinical follow-up periods were 62.2 ± 34.04months (range, 24-169months) and 94.9 ± 45.41months (range, 24-175months), respectively. At 2, 6, and 12years, the tumor control rates were 100%, 95.7%, and 85.0%, respectively. Tumor shrinkage occurred in 92.6% of patients (n = 50), tumor volume remained stable in 5.6% of patients (n = 3), and tumor growth occurred in 1.9% of patients (n = 1). At a median follow-up of 53.5months, the pre-GKRS tumor volume significantly decreased to 2.35 cm3 (p < 0.001). While Koos grade 3 patients had a greater possibility of attaining higher volume reduction, "multiple small thick-walled cyst pattern" and smaller tumor volumes decreased the likelihood of achieving higher volume reduction. Serviceable hearing (Gardner-Robertson Scale I-II) was present in 16.7% of patients prior to GKRS and it was preserved in all of these patients following GKRS. After GKRS, 1.9% of patients (n = 1) had new-onset trigeminal neuralgia. There was no new-onset facial palsy, hemifacial spasm, or hydrocephalus. Contrary to what was believed, our findings suggest that upfront GKRS seems to be a safe and effective treatment option for large cVSs.

Facial Nerve Function Outcome and Risk Factors in Resection of Large Cystic Vestibular Schwannomas.

Objective Cystic vestibular schwannomas (VS) in contrast to solid VS tend to have accelerated growth, larger volume, rapid/atypical presentation, lobulated/adherent surface, and unpredictable course of the cranial nerves. Cystic VS are surgically challenging, with worse clinical outcomes and higher rate of subtotal resection (STR). Methods We retrospectively analyzed postoperative outcomes of 125 patients with cystic VS, operated between years 2005 and 2019 in our center. We confronted the extent of the resection and House-Brackmann (HB) grade of facial palsy with the results of comparable cohort of patients with solid VS operated in our center and literature review by Thakur et al. 1 Results Translabyrinthine approach was preferred for resection of large, cystic VS (97.6%). Gross-total resection (GTR) was achieved in 78 patients (62.4%), near-total resection (NTR) with remnant (<4 × 4 × 2 mm) in 43 patients (34.4%), and STR in 4 patients (3.2%). NTR/STR were significantly associated with higher age, tumor volume >5 cm 3 , retrosigmoid approach, high-riding jugular bulb, tumor adherence to the brain stem, and facial nerve ( p = 0.016; 0.003; 0.005; 0.025; 0.001; and <0.00001, respectively). One year after the surgery, 76% of patients had HB grades 1 to 2, 16% had HB grades 3 to 4, and 8% had HB grades 5 to 6 palsy. Worse outcome (HB grades 3 to 6) was associated with preoperative facial palsy, tumor volume >25 cm 3 , and cyst over the brain stem ( p = 0.045; 0.014; and 0.05, respectively). Comparable solid VS operated in our center had significantly higher HB grades 1 to 2 rate than our cystic VS (94% versus 76%; p = 0.03). Comparing our results with literature review, our HB grades 1 to 2 rate was significantly higher (76% versus 39%; p = 0.0001). Tumor control rate 5 years after surgery was 95.8%. Conclusion Our study confirmed that microsurgery of cystic VS has worse outcomes of facial nerve preservation and extent of resection compared with solid VS. Greater attention should be paid to the above-mentioned risk factors.

Retrosigmoid Approach for Resection of Large Cystic Vestibular Schwannoma.

Objectives This video was aimed to describe the surgical indications, relevant anatomy, and surgical steps of retrosigmoid approach for resection of a large cystic vestibular schwannoma (VS). Design The operative steps are described in a surgical instructional video. Setting The surgery took place at a tertiary skull base referral center. Participant Patient is a 62-year-old man who reported with right sided profound hearing loss with no word recognition, progressive dizziness and tinnitus, excruciating burning pain in the V2 distribution of right trigeminal nerve, wide-based gait, and a right cerebellopontine angle (CPA) cystic VS measuring 3.3 cm. Main Outcome Measures The large cystic VS was resected through retrosigmoid approach. Results The surgery resulted in removal of the large cystic VS with initial delayed facial weakness that completely resolved (House Brackmann grade 1) by 3 month follow-up. The patient had no other postoperative complications and is convalescing well from the procedure. Conclusion Cystic VS presents some unique challenges compared with their solid counterparts. The cystic tumor capsule may be very adherent to the adjacent structures, and distinguishing thin cyst walls from the arachnoid of the CPA, can be quite challenging. The retrosigmoid approach provides adequate surgical exposure for VS tumor resection. The link to the video can be found at: https://youtu.be/sFNvRWG465Q .

Treatment Outcome of Gamma Knife Radiosurgery of Vestibular Schwannomas with Cystic Component

Objective: Many studies have shown favorable outcome of Gamma knife radiosurgery (GKRS) for vestibular schwannomas (VSs). However, there have been few studies which have shown the treatment result of cystic VSs (CVSs) for GKRS. The aim of this study was to confirm whether GKRS for CVSs continues to be safe and effective. Methods: The study population consisted 511 patients (172 males, 339 females) with VSs treated with GKRS between May 1990 and December 2013. Group 1 defined as cyst/tumor volume >30%, group 2 was cyst/tumor volume >50%, and group 3 was solid tumor or cyst/tumor volume ≤30%. To analyze factors that correlated with treatment outcomes, the following factors were assessed: tumor volume, cyst volume, tumor/cyst ratio, cyst type (single vs. multicystic), previous resection history, marginal radiation dose. Results: The median follow up period was 52 months (range, 12-110 months). Tumor progression in group 1 was 5 (18.5%), group 2 was 1 (11.1%) and group 3 was 31 (6.4%). In group 1, 2 patients underwent delayed microsurgery at 31 and 36 months after GKRS. Conclusion: In this study we found that GKRS for large CVS was associated with poor treatment outcome. Further study is needed to identify the mechanism of the tumor progression of CVS after GKRS

A stepwise illustration of the translabyrinthine approach to a large cystic vestibular schwannoma

Of the presigmoid approaches, the translabyrinthine approach is often used when a large exposure is needed to gain access to the cerebellopontine angle but when hearing preservation is not a concern. At the authors' institution, this approach is done with the aid of ENT/otolaryngology for temporal bone drilling and exposure. In the present article and video, the authors demonstrate the use of the translabyrinthine approach for resection of a large cystic vestibular schwannoma, delineating the steps of positioning, opening, temporal bone drilling, tumor resection, and closure. Gross-total resection was achieved in the featured case. The patient's postoperative facial function was House-Brackmann Grade II on the side ipsilateral to the tumor, although function improved with time. The translabyrinthine route to the cerebellopontine angle is an excellent approach for masses that extend toward the midline or anterior to the pons. Although hearing is sacrificed, facial nerve function is generally spared.

Surgical Outcomes for Large Cystic Vestibular Schwannomas

Introduction: Cystic vestibular schwannomas (CVSs) are rare and thought to present different clinical, radiological, and treatment outcomes from their solid counterparts.

Facial nerve function after large cystic vestibular schwannomas surgery via the retrosigmoid approach

To evaluate long-term postoperative facial nerve function in patients undergoing large cystic vestibular schwannomas (VSs) surgery. Surgical outcome of 36 patients with large cystic VS was retrospectively assessed, and compared with a group of 67 patients with large solid VS. The anatomical integrity of the facial nerve was preserved in 88.9% of cystic group patients and in 92.5% of solid group patients. At 1 year after surgery, 75.8% of the patients with cystic VSs had favorable facial nerve function and 24.2% had poor function. There was no significant difference in facial nerve outcomes between cystic and solid tumors. When the cyst wall was closely adherent to the facial nerve, near total or subtotal resection was associated with a better facial nerve outcome compared to total excision (P < 0.05). In most cystic VS patients, favorable facial nerve function can be attained by surgical treatment via retrosigmoid approach. Special care should be taken to remove entire cystic VSs as well as partial cystic VSs with anterior or medial located cysts. When a dissection plane cannot be developed between the cyst wall and the facial nerve, near total or subtotal resection is of benefit for facial nerve function.

Hemorrhage into Cystic Vestibular Schwannoma Following Stereotactic Radiation Therapy

The occurrence of a hemorrhage into a vestibular schwannoma is a rare phenomenon. Several reports, however, indicate a risk profile for a subgroup of patients with vestibular schwannoma which show hypervascularity in the histopathological examination. Cystic formation, large size, mixed Antoni type and anticoagulation therapy seem to enhance the risk of tumor hemorrhage. We report on a patient with a large cystic vestibular schwannoma who died from fatal bleeding into the tumor 15 months following stereotactic radiation therapy. Since hemorrhage seems to be a relevant risk in large cystic vestibular schwannomas, a surgical treatment should be preferred whenever possible.

Acute Intratumoral Bleeding in a Cystic Vestibular Schwannoma: Case Report

Introduction: Vestibular schwannomas are slow-growing tumors with progressive hearing and vestibular symptoms as the usual presentation. Cystic degeneration in schwannomas are found not so rarely, and it is probably secondary to microhemorrhages inside the tumor. We report a very unusual case of vestibular schwannoma with a massive hemorrhage inside the tumor and abrupt clinical presentation. Methods: We reviewed the cases of vestibular schwannomas treated by the authors with particular attention to their presentation symptoms and the occurrence of associated cysts. Results: We report a case of a 52-year-old female with acute presentation symptoms of intracranial hypertension and compression of the brain stem due to a large cystic vestibular schwannoma with massive bleeding inside the cyst. Total removal of the tumor was obtained through a suboccipital retrosigmoidal approach after the drainage of the hemorrhagic collection inside the tumor. Pathological studies confirmed hemosiderin deposition in the walls of the cyst. Conclusions: We report the CT and MR imaging appearance and the operative findings of a very rare case of massive intratumoral bleeding in a vestibular schwanoma. This unusual and unpredictable occurrence would be considered as an additional risk in the cases treated conservatively or with gamma-knife.