Imaging characteristics and surgical management of orbital neurilemmomas.

Aim: To review imaging characteristics and surgical outcomes of orbital neurilemmoma.

Methods: Retrospective review of 21 patients with orbital neurilemmoma managed at the Zhongshan Ophthalmic Center of Sun Yat-sen University from June 2005 to December 2016. All patients underwent surgical excision following preoperative imaging including ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI).

Results: Among these patients, 11 were male and 10 were female, with age ranging from 12 to 75y (average, 40.3y). Ultrasound of the orbit showed a roundish well-demarcated orbital mass with low or middle internal reflectivity in each case. Dark inner liquid fields were detected in 28.6% of these cases. Doppler ultrasound demonstrated blood flow signals in these masses. CT showed that the tumors were either homogeneous or heterogeneous. MRI of T1WI revealed isointense or hypointense tumors, while the T2WI indicated heterogeneous hyperintense lesions. Gd contrast MRI demonstrated heterogenous or homogeneous enhancement initiating from the wide area of the lesion. Six patients underwent lateral orbitotomy and 15 anterior orbitotomy. All tumors were completely removed. After a mean follow-up of 1.8y, 3 patients experienced reduced vision while the remaining 10 patients showed improved vision after surgery. One patient experienced a mild limitation of upward motility. No recurrence occurred.

Conclusion: Orbital neurilemmoma is a relatively rare, benign orbital tumor. Effective diagnosis requires a combination of ultrasonography, CT and/or MRI. These imaging techniques are also vital to differentiate neurilemmomas from other orbital masses like that of cavernous hemangiomas and meningiomas. Successful treatment requires complete resection of the neurilemmomas as performed either by lateral or anterior orbitotomy. Recurrence is rare after complete removal.