Primary orbital sarcoma in adults: a case series with emphasis on post-irradiation sarcoma.

Adult primary orbital sarcomas are rare. They can comprise a variety of tumour types and are difficult to treat. Irradiation is a significant risk factor, and the incidence of post-irradiation sarcoma of the orbit may be increasing due to the widespread use of radiotherapy and improved survival of patients with cancer. Post-irradiation sarcoma should be considered in the differential diagnosis of an orbital space-occupying lesion in a patient with a history of radiotherapy.