Preoperative Differences in Intracranial Facial Versus Vestibular Schwannomas: A Four Nerve Assessment.

OBJECTIVES: Assesses whether preoperative functional testing can distinguish vestibular schwannomas from facial nerve schwannomas medial to the labyrinthine segment. STUDY DESIGN: Retrospective cohort. METHODS: Retrospectively review surgically managed intracranial facial and vestibular schwannomas between January 2015 and December 2019 at two tertiary care centers. Patients with neurofibromatosis 2 and surgery for recurrence were excluded. Preoperative functional testing to include House-Brackmann scores, electroneuronography (ENoG), cervical vestibular evoked myogenic potentials (cVEMP), caloric testing, acoustic brainstem responses (ABRs), acoustic reflexes, and audiograms was compared between the two groups of schwannomas. RESULTS: Twelve facial and 128 vestibular schwannomas met inclusion criteria. In only one case was a facial schwannoma diagnosed preoperatively from imaging. No statistically significant difference was found in preoperative House-Brackmann scores, ENoG, cVEMP, caloric testing, ABRs, or acoustic reflexes. Pure tone average was worse in the vestibular schwannoma group (63 dB [95% CI: 58-68 dB] vs. 46 dB [95% CI: 34-58 dB], P = .01), and the difference was more apparent in the lower frequencies. Word recognition score was better in the facial schwannoma group (66% [95% CI: 45-86%] vs. 41% [95% CI: 34-47%], P = .02). CONCLUSION: Specialized preoperative functional evaluation of the nerves of the internal auditory canal cannot reliably predict the presence of an intracranial facial schwannoma. Hearing is better in facial schwannomas, particularly in the lower frequencies. This should raise the index of suspicion for an intracranial facial schwannoma, especially in candidates for hearing preservation vestibular schwannoma surgery. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2098-2105, 2021.

Endoglin-based assessment of neoangiogenesis in sporadic VIII cranial nerve schwannoma.

Although the diagnosis and treatment of sporadic vestibular schwannoma has improved in recent years, no factors capable of predicting its growth have been identified as yet. Endoglin (CD105) is a proliferation-associated protein expressed in angiogenic endothelial cells, and a potential prognostic indicator for several solid tumors. The aim of the present study was primarily to investigate the expression and role of CD105 in a series of sporadic vestibular nerve schwannomas. In 71 consecutive cases of vestibular schwannoma, vessel cross-sectional area and density were calculated from immunohistochemically assessed CD105 expression using image analysis to correlate them with: (i) tumor dimensions; and (ii) tumor growth rate measured on high-resolution contrast-enhanced MRI (ceMRI). Based on assessments of CD105 expression, a significant positive correlation was identified between vessel cross-sectional area and tumor size at the time of surgery (p = 0.0024), and between vessel density and tumor size (p = 0.013). Vessel cross-sectional area (p = 0.0006) and vessel density (p = 0.003) were significantly greater in tumors measuring ≥10 mm in size than in those <10 mm. Conversely, when tumor growth rate could be calculated from two or more ceMRI (38 cases), there was no significant correlation between tumor growth rate and cross-sectional vessel area or vessel density as assessed with CD105. Further investigations are needed to ascertain the feasibility of: (i) using circulating endoglin assay to monitor tumor growth; and (ii) targeting neoangiogenesis with anti-endoglin antibodies in sporadic vestibular schwannoma.

Gamma Knife radiosurgery for larger-volume vestibular schwannomas. Clinical article.

OBJECT: Stereotactic radiosurgery (SRS) is an important management option for patients with small- and medium-sized vestibular schwannomas. To assess the potential role of SRS in larger tumors, the authors reviewed their recent experience. METHODS: Between 1994 and 2008, 65 patients with vestibular schwannomas between 3 and 4 cm in one extracanalicular maximum diameter (median tumor volume 9 ml) underwent Gamma Knife surgery. Seventeen patients (26%) had previously undergone resection. RESULTS: The median follow-up duration was 36 months (range 1-146 months). At the first planned imaging follow-up at 6 months, 5 tumors (8%) were slightly expanded, 53 (82%) were stable in size, and 7 (11%) were smaller. Two patients (3%) underwent resection within 6 months due to progressive symptoms. Two years later, with 63 tumors overall after the 2 post-SRS resections, 16 tumors (25%) had a volume reduction of more than 50%, 22 (35%) tumors had a volume reduction of 10-50%, 18 (29%) were stable in volume (volume change < 10%), and 7 (11%) had larger volumes (5 of the 7 patients underwent resection and 1 of the 7 underwent repeat SRS). Eighteen (82%) of 22 patients with serviceable hearing before SRS still had serviceable hearing after SRS more than 2 years later. Three patients (5%) developed symptomatic hydrocephalus and underwent placement of a ventriculoperitoneal shunt. In 4 patients (6%) trigeminal sensory dysfunction developed, and in 1 patient (2%) mild facial weakness (House-Brackmann Grade II) developed after SRS. In univariate analysis, patients who had a previous resection (p = 0.010), those with a tumor volume exceeding 10 ml (p = 0.05), and those with Koos Grade 4 tumors (p = 0.02) had less likelihood of tumor control after SRS. CONCLUSIONS: Although microsurgical resection remains the primary management choice in patients with low comorbidities, most vestibular schwannomas with a maximum diameter less than 4 cm and without significant mass effect can be managed satisfactorily with Gamma Knife radiosurgery.

The growth of acoustic neuromas in volumetric radiologic assessment.

OBJECTIVE: The volumetric assessments of neuroma were applied for radiologic observation of tumor growth. The hypothesis that most of neuromas are stable or show only slight growth was tested. STUDY DESIGN: This was an observational study. SETTING: The study was performed in the university centers. PATIENTS: The study group included 27 patients with 15 unilateral tumors and 12 bilateral tumors. All patients had at least 2 magnetic resonance imaging (MRI) examinations, and the average interval between initial and control examinations was 11.4 months. MAIN OUTCOME MEASURE: Volume measurements were performed on T1- weighted MRI spin echo sequences after injection of gadolinium using special software. Growth of the tumors was estimated by comparison of the results of three measurements from the initial and control MRI examinations. RESULTS: The growth was confirmed in 17 of 27 tumors (63%). Growth was found in 10 of 12 neuromas of neurofibromatosis type 2 (83.7%). In 15 unilateral neuromas, growth was found in 7 (43%). Unilateral neuromas were observed for a shorter period of time (6.3 months) than bilateral tumors (14.7 months). The correlation between a neuroma volume gain and the follow-up period was statistically significant (p = 0.003, r = 0.544). CONCLUSIONS: The growth of tumors can be confirmed despite a short follow-up period.

Quality of life after acoustic neuroma surgery.

A questionnaire was sent to 134 patients who had undergone surgery for a unilateral acoustic neuroma between 1980 and 1993, to obtain data on the consequences on their quality of life, physical condition, social life, employment, and use of medical facilities. Distinctions were made between the translabyrinthine-transotic approach, the suboccipital approach, the tumor size, and the number of operations per patient. We found that the patients' reported state of health after surgery was poorer than that in a group of comparable nonoperated patients. Recuperation after an operation took many months and did not always result in full recovery. Surgery had various effects on preoperative symptoms such as hearing loss, tinnitus, vertigo, and facial nerve dysfunction: improvement, no change, or deterioration. Surgery had severe consequences on social life and occupation, but far less effect on income. Almost one third of the patients required postoperative home help, and a proportion were declared unfit to work. The surgical approach, tumor size, and reoperations had a definite influence on the study parameters. After suboccipital surgery, there were more reports of pain, more declarations of incapacity to work, poorer facial nerve function, and more frequent visits to the general practitioner. The translabyrinthine-transotic approach was associated with more severe pain and more complaints of postoperative vertigo. A greater proportion of the patients with larger tumors were declared unfit to work. The general state of health after suboccipital reoperations was better than after the initial operation; there was no reasonable explanation for this. Facial nerve function deteriorated after reoperation(s).

Vagal paragangliomas: a clinical, pathological, and DNA assessment.

Ten vagal paragangliomas were studied by image analysis and the results correlated with clinicopathologic features to determine if the DNA ploidy pattern could be used to separate benign from malignant paragangliomas. The tumours occurred in 8 women and 2 men ranging in age from 23 to 75 years (average 54 years). Follow-up was available in all 10 patients and ranged from 3 months to 27 years (average 7.8 years). Of the 10 tumours examined for DNA, 5 were diploid, 4 diploid-tetraploid, and 1 aneuploid. Two patients experienced local recurrences. One of these had a diploid tumour that recurred 22 years after excision and the other had an aneuploid tumour which recurred 4 years 4 months later and was associated with cervical lymph node metastasis. Two patients had malignant tumours with histologically confirmed metastases to noncontiguous cervical lymph nodes. One of the malignant tumours was diploid and the other aneuploid. This study concludes that DNA abnormalities are common in vagal paragangliomas and that tumour ploidy can not be used to assess malignant potential.