[Solitary orbital schwannomas: clinical, imaging, and surgical features]

Schwannoma is a rare peripheral nerve tumor of the orbit, the diagnosis of which can only be made with certainty by histopathological examination. We report our experience on the clinical, imaging, and surgical aspects of orbital schwannomas based on our series of six patients.

We retrospectively reviewed the records of six patients managed at our institution for orbital schwannoma. The age, sex, presenting clinical signs and symptoms, pre- and postoperative visual acuities, magnetic resonance imaging (MRI) features, the surgical techniques employed, and the pitfalls encountered were recorded.

There were three female and three male patients. The mean age at diagnosis was 39.5 years. Decreased visual acuity and proptosis were the most common presenting signs. MRI studies showed that schwannoma was hypointense on T1- and slightly hyperintense on T2-weighted images. With the exception of degenerated or myxoid parts of the tumor, there was variable enhancement following gadolinium injection. The tumor was totally removed via the transconjunctival approach in five patients and through a subbrow cutaneous incision in one patient. There was no recurrence during a mean follow-up of 2.2 years.

Most orbital schwannomas, whether intraconal or extraconal, can be safely excised through the transconjunctival approach. Meticulous dissection is mandatory to separate the tumor from its surroundings. Cryoextraction may not be advisable because of the risk of fragmentation of the tumor due to its weak pseudoencapsulation.