446 Management of Orbital Schwannomas, to Operate or Not? A Population-Based Case Series

INTRODUCTION: Schwannomas of the orbit (OS) are rare occurrences with no more than 500 cases documented worldwide. Traditionally, once discovered radical excision of the tumor, often requiring a multidisciplinary neuroophthalmological and neurosurgical approach, is sought to prevent tumor invasion of the delicate neuro-ophthalmic structures. However, inherent surgical risks, due to the complexity of the neurovascular configuration in the orbital region, warrant further investigation of a more conservative approach in the management of these benign entities. METHODS: The study center is the primary referral center for multidisciplinary evaluation, discussion, and management of orbital tumors, including schwannomas, in Sweden. During the period of 2005-2010, 16 patients with an OS diagnosis were identified and managed at the center. RESULTS: After weighing the risks and benefits of surgical and conservative treatment, four patients underwent immediate surgery where gross total resection (GTR) was achieved in 3 cases (75%). The remaining 12 patients were treated conservatively by watchful waiting and re-evaluation. Surgery with subtotal resection (STR) was later performed after an average of 17 months in three of these patients (25%). No recurrences or regrowth were detected on radiographic follow-up (mean 50 months), and all patients experienced postoperative improvement at clinical follow-up (mean 65 months). The remainder of the conservatively treated patients (n = 9) experienced no clinical progression (mean 30 months). A slight radiological tumor progression was only detected in one patient after 17 months. CONCLUSIONS: There were no differences in outcome between patients undergoing immediate surgery and those operated later after watchful waiting. Conservatively treated patients had minimal to no symptoms and remained clinically stable throughout the follow-up period. Based on these findings, watchful waiting, may successfully be adopted in cases whit mild symptoms and no imminent risk of neuro-ophthalmic impairment.