Osseous choristoma of the conjunctiva simulating extraocular extension of retinoblastoma.

Abstract

To report the clinicopathologic features of an epibulbar osseous choristoma simulating extraocular extension of retinoblastoma. Interventional case report. A 7-month-old male presented with a unilateral intraocular mass localized to the temporal retina and a white pedunculated lesion extending from the conjunctiva, anterior to the insertion of the lateral rectus muscle. Clinical examination and computed tomography scan findings led to the diagnosis of retinoblastoma with extraocular extension. The child underwent excision of the epibulbar lesion and enucleation of the globe. The histopathologic examination of the epibulbar lesion revealed an osseous choristoma. The intraocular contents displayed features typical of retinoblastoma without extraocular extension. An epibulbar osseous choristoma can simulate extraocular extension of retinoblastoma in an eye harboring the intraocular malignancy.