Outcome analysis of 40 cases of vestibular schwannoma: A comparison of sitting and Park bench surgical position

The present study retrospectively reviews our experience in 40 cases of vestibular schwannoma, operated between the years 1995 and 2002. All the patients underwent tumour resection either in sitting or in the Park bench position via the suboccipital retromastoid route. The position of the patient was selected arbitrarily. Precordial Doppler echocardiography was used to monitor air embolism. Operative results, including the size of the tumour, completeness of resection, anatomical and functional preservation of the facial nerve, operative complications and mortality were analysed and compared in these two operative positions. There was no statistically significant difference in terms of surgical results between these two groups.      

Mediastinal Ancient Schwannoma Causing Intrathoracic Bleeding

Spontaneous hemothorax caused by the rupture of a benign schwannoma has rarely been reported. Herein, we present the successful excision of an extremely rare case of mediastinal ancient schwannoma causing intrathoracic bleeding. A 27-year-old man was admitted to our emergency department because of back pain and dyspnea. Computed tomography revealed massive pleural effusion with a posterior mediastinal tumor. We performed a resection of the tumor which had ruptured, and the tumor was diagnosed as an ancient schwannoma.     

Evaluation of pure-tone audiometric protocols in vestibular schwannoma screening

The objective was to evaluate the pure-tone audiogram-based screening protocols in VS diagnostics. We retrospectively analyzed presenting symptoms, pure tone audiometry and MRI finding from 246 VS patients and 442 controls were collected to test screening protocols (AAO-HNS, AMCLASS-A/B, Charing Cross, Cueva, DOH, Nashville, Oxford, Rule3000, Schlauch, Seattle, Sunderland) for sensitivity and specificity. Results were pooled with data from five other studies, and analysis of sensitivity, specificity and positive likelihood ratio (LR+) for each protocol was performed. Our results show that protocols with significantly higher sensitivity (AMCLASS-A/B, Nashville) show also significantly lowest specificity, and tend to have low association (positive likelihood ratio, LR+) to the VS. The highest LR+ was found for protocols AAO-HNS, Rule3000 and Seattle. In conclusions, knowing their properties, screening protocols are simple decision-making tools in VS diagnostic. To use the advantage of the highest sensitivity, protocols AMCLASS-A + B or Nashville can be of choice. For more reasonable approach, applying the protocols with high LR+ (AAO-HNS, Rule3000, Seattle) may reduce the overall number of MRI scans at expense of only few primarily undiagnosed VS.     

Determining Benchmarks in Hearing Preservation Surgery for Vestibular Schwannoma

Objectives The objectives of this study were to determine minimal benchmarks of success in vestibular schwannoma hearing preservation surgery, wherein the likelihood of having preserved hearing in a single patient is at least as likely as having created a poor facial nerve outcome for a single patient.Design This is a statistical analysis of published literature.Setting Academic Tertiary Medical Center.Main Outcome Measures Based on published natural history data, the number needed to treat (NNT) equation was used to calculate the minimally acceptable hearing preservation rates within various hearing classification schemes.Results Given good facial nerve outcome rates of 85, 90, and 95%, the corresponding hearing preservation rates at 4.7 years that are likely to preserve classes A and B hearing (American Academy of Otolaryngology-Head and Neck Surgery classification) in a single patient as to cause a poor facial nerve outcome are 70, 65, and 60%, respectively. If surgery is limited exclusively to intracanalicular tumors, these rates drop to 62, 57, and 52%, respectively. If the word recognition scoring classification is used, required hearing preservation rates are higher.Conclusion It is possible to use the NNT equation alongside projected facial nerve outcomes to estimate benchmarks of minimally acceptable hearing preservation rates.     

GASTRIC SCHWANNOMA WITH ADJACENT EXTERNAL PROGRESSION HARBORED ABERRANT NF2 GENE

Gastric schwannomas are rare benign mesenchymal tumors. We describe a schwannoma of gastric origin with adjacent external progression. Sections showed a spindle cell tumor arranged in interlaced bundles and fascicles that was S‐100 and CD34 positive but c‐KIT protein negative. Histology and immunohistochemistry revealed the typical appearance of a gastric schwannoma. Genetic evaluation revealed that the tumor harbored a point mutation in exon 6 of the tumor suppressor neurofibromatosis 2 (NF2) gene, which resulted in an amino acid substitution of NF2 protein, and no mutation in exon 4b of the NF1 gene. In conclusion, we identified a rare mutation of the NF2 gene in gastric schwannoma. A diagnosis can only be definitive when based on histological and immunohistochemical findings. Digestive tract schwannomas are rare mesenchymal tumors that are differentiated from gastrointestinal stromal tumors by the absence of KIT protein. Follow up suggested that complete resection is an effective long‐term treatment strategy.     

Ancient Schwannoma of the Oral Floor and Ventricular Portion of the Tongue: A Case Report and Review of the Literature

We report a case of ancient schwannoma, which is a rare benignneoplasm of the oral floor and ventricular portion of the tongue.Only two cases have previously been reported in the Englishliterature. The present tumor, measuring 5.5 x 3.0 x 3.0 cm,was the largest of the three. To differentiate ancient schwannomafrom schwannoma with malignant transformation, it is importantto confirm the absence of abrupt transition between areas ofapparently typical schwannoma and areas composed of atypicallarge cells with pleomorphic and hyperchromatic nuclei, as wellas the absence of mitoses, necrosis, and invasiveness. In thepresent case, calcification was not detected, nor was hyalinizationextensive, although many of the neoplastic Schwann cells showeddegenerative nuclear atypia.     

MR findings in intralabyrinthine schwannomas

AIM: Intralabyrinthine schwannomas (ILS) are rare benign tumours. They are not always recognized on routine magnetic resonance imaging (MRI). We aimed to study the clinical presentation and MRI findings in our patients with ILS. MATERIALS AND METHODS: Retrospective analysis of patients with vestibular schwannomas treated at this center. RESULTS: Of 144 vestibular schwannomas studied at this centre, three patients had an ILS. The most common presenting symptoms were unilateral hearing loss, tinnitus and vertigo. Two patients demonstrated a progressive sensorineural hearing loss (SNHL). The third patient had a severe SNHL at presentation. MRI enhanced with contrast medium was positive in the two patients with progressive SNHL and negative in the patient with the severe SNHL. CONCLUSION: This series demonstrates the ability of MRI to identify schwannomas filling the labyrinth, and also its inability to identify extremely small ILS. It underlines the importance of sending the cristae of patients undergoing labyrinthectomy for presumed Ménière's disease for histological examination.     

Incidence of cerebrospinal fluid leak after microsurgical removal of vestibular schwannomas

Summary.  Objectives: Cerebrospinal fluid (CSF) leak still remains an unresolved problem after microsurgical removal of vestibular schwannomas (VS).  Methods: 14 (6%) Cases of cerebrospinal fluid rhinorrhea and 3 cases with subcutaneous retro-auricular CSF collection, occurring in a series of 224 patients operated on by the senior author (JMG) on VS between 1989–2000 via the suboccipital retrosigmoidal approach were studied retrospectively. Prophylaxis of CSF leak was usually attempted by packing the unroofed posterior wall of internal acoustic meatus with muscle. The mastoid air cells were packed first with collagen then with muscle and bone dust.  Results: All CSF leaks were diagnosed within 2–7 days after surgery. We found no relation to tumour size. Treatment was initiated in all patients with continuous external lumbar cerebrospinal fluid drainage (CELCFD) for 7 days. In 11 cases with CSF rhinorrhea and all cases with retro-auricular CSF collection, the CSF leak was stopped. However, in 3 cases the CSF leak persisted despite the lumbar drain. These patients were operated on again with sealing the IAM and the mastoid cells again with muscle and collagen. No recurrence of CSF leak was noted after the second operation. There was no case of late onset CSF leak during the follow-up of one year.  Conclusion: Although CSF leak is a common complication (6%) after vestibular schwannoma removal, aggressive treatment is required only in a few cases (1%). Most of the cases are successfully treated by (CELCFD). The suboccipital approach offers an advantage of opening only a part of mastoid air cells, which are in our opinion the second most common site of CSF leakage. Published online October 10, 2002 Correspondence: A. Bani M.D., Neurochirurgische Klinik, Klinikum Duisburg, Wedau Kliniken, Zu den Rehwiesen 9, 47055 Duisburg, Germany.