Atypical Schwannoma: A 10-year experience.

OBJECTIVE: The goal of this study was to describe the clinical presentation associated with atypical schwannoma of the cerebellopontine angle, characterize the pathologic findings and describe the long-term outcome. MATERIALS AND METHODS: The study design was retrospective case review of patients with the histopathologic diagnosis of atypical and benign schwannoma of the cerebellopontine angle diagnosed at the study institution over a 10-year period. SETTING: Tertiary referral center. MAIN OUTCOMES MEASURE: Demographic data of the cohort were recorded. Findings on pathology were evaluated. Initial treatment and post-operative course was recorded. Main outcome measures were clinical presentation, including cranial nerve deficits at the time of presentation, complication and recurrence rates. RESULTS: At presentation, a somewhat accelerated course of cranial nerve deficit was noted among patients with atypical schwannoma as compared to benign schwannoma. In the immediate post-operative period, there were no differences noted in the complication rate. Atypical schwannomas appear to have higher recurrence rate compared to benign schwannomas. CONCLUSIONS: Atypical schwannoma is an intermediate disease process with an accelerated clinical course and higher recurrence rate as compared to vestibular schwannoma. Traditional operative approaches may be employed without increased concern for post-operative complications. Thorough counseling and close follow-up should be offered to these patients given the higher recurrence rate. Larger studies are required to determine if these patients need more frequent MRIs for long-term surveillance.

Heterotopic Mucosal Grafting Enables the Delivery of Therapeutic Neuropeptides Across the Blood Brain Barrier.

BACKGROUND: The blood-brain barrier represents a fundamental limitation in treating neurological disease because it prevents all neuropeptides from reaching the central nervous system (CNS). Currently, there is no efficient method to permanently bypass the blood-brain barrier. OBJECTIVE: To test the feasibility of using nasal mucosal graft reconstruction of arachnoid defects to deliver glial-derived neurotrophic factor (GDNF) for the treatment of Parkinson disease in a mouse model. METHODS: The Institutional Animal Care and Use Committee approved this study in an established murine 6-hydroxydopamine Parkinson disease model. A parietal craniotomy and arachnoid defect was repaired with a heterotopic donor mucosal graft. The therapeutic efficacy of GDNF (2 µg/mL) delivered through the mucosal graft was compared with direct intrastriatal GDNF injection (2 µg/mL) and saline control through the use of 2 behavioral assays (rotarod and apomorphine rotation). An immunohistological analysis was further used to compare the relative preservation of substantia nigra cell bodies between treatment groups. RESULTS: Transmucosal GDNF was equivalent to direct intrastriatal injection at preserving motor function at week 7 in both the rotarod and apomorphine rotation behavioral assays. Similarly, both transmucosal and intrastriatal GDNF demonstrated an equivalent ratio of preserved substantia nigra cell bodies (0.79 ± 0.14 and 0.78 ± 0.09, respectively, P = NS) compared with the contralateral control side, and both were significantly greater than saline control (0.53 ± 0.21; P = .01 and P = .03, respectively). CONCLUSION: Transmucosal delivery of GDNF is equivalent to direct intrastriatal injection at ameliorating the behavioral and immunohistological features of Parkinson disease in a murine model. Mucosal grafting of arachnoid defects is a technique commonly used for endoscopic skull base reconstruction and may represent a novel method to permanently bypass the blood-brain barrier.