Appearances of choroidal osteomas with diagnostic imaging.

The diagnostic imaging appearances of three choroidal osteomas (osseous choristomas) are presented. This rare, benign choroidal tumour is being recognized with increasing frequency, and is important to remember in the differential diagnosis of any unusual mass in the ocular fundus lest it be mistaken for a more sinister lesion. All three osteomas were demonstrated by ocular ultrasound (US), fluorescein angiography (FA) and computed tomography (CT) but none by plain radiography. None of the lesions was visible on magnetic resonance imaging (MRI); the reason for this is probably the bony nature of the tumours. The appearances of choroidal osteomas on US, FA, plain radiography and CT are discussed. To our knowledge this is the first report of a series of choroidal osteomas investigated by MR.