Orbital schwannoma with cystic degeneration.

Background: Schwannoma is a benign, slowly growing, painless, peripheral nerve sheath tumour that is uncommon in orbit. Longstanding tumours may develop degenerative changes. Extensive cystic change in orbital schwannoma is quite rare. We conducted this study to analyse the cases of orbital schwannoma, which were predominantly cystic and describe their clinical, imaging and histopathological features.

Method: A retrospective analysis of histopathology records of all the orbital tumours operated between 1993 and 2008 was undertaken at a tertiary care referral centre in northern India. The clinical, imaging and histopathological features of patients with cystic schwannoma were studied.

Results: A total of 600 specimens of orbital tumours were received during the study period. We found 39 cases of orbital schwannoma. Out of these, 16 (41%) had extensive cystic degeneration. The age of these patients ranged from 20 to 65 years. Eleven of the patients were female. Duration of symptoms varied from 3 months to 15 years. The most common clinical symptom was painless progressive proptosis with diminution of vision. The radiological picture was quite variable resulting in a primary diagnosis of combined venous-lymphatic vascular malformation in 2, lacrimal gland tumour in 2, dermoid cyst in 1, hydatid cyst in 2 and schwannoma in 5 cases.

Conclusion: Orbital schwannoma is a great masquerader in the orbit. Extensive cystic changes in schwannoma are uncommonly reported. Cystic schwannoma constituted 41% of all orbital schwannomas in our series. To the best of our knowledge, this is the largest case series of orbital cystic schwannomas.