Inferior oblique schwannoma: diagnosis and management.
BACKGROUND
Orbital schwannoma accounts for less than 5% of orbital tumours and few cases arising in the superior orbit are reported in the literature.


OBJECTIVE
To present, to our knowledge, the first report of inferior oblique-associated orbital schwannoma.


METHODS
Interventional case report with clinical photographs, MRI imaging, intra-operative photographs and histology.


RESULTS
A 68 year-old man presented with decreased right vision and double vision in downgaze. Examination revealed a right 3 mm ptosis, hypertropia and limitation of depression. Exploration and excision, via anterior orbitotomy, and histological examination confirmed a schwannoma located within the right inferior oblique muscle. Vision normalised post-operatively and there has been no clinical or radiological recurrence of the lesion at 2 years.


CONCLUSIONS
This rare case highlights that schwannoma may occur in association with the inferior oblique complex and we suggest that schwannomas should now be considered in the differential diagnosis when patients present with a clinically-suspected or radiologically-proven orbital mass.
D000368:Aged; D003937:Diagnosis, Differential; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009442:Neurilemmoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D009918:Orbital Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery