Decalcification of a choroidal osteoma. A 56-year-old man presented with a clearly defined orange tumour in the posterior pole of his left eye. A choroidal osteoma was suspected, and ultrasonography confirmed the diagnosis. Fluorescein angiography demonstrated subretinal neovascularisation on the nasal edge of the tumour, which was treated with krypton laser photocoagulation twice. Recurrent subretinal neovascularisation occurred one year later and was not amenable to treatment. Three years after the patient first presented, thinning of the tumour was noted on follow-up examination. During the next 15 months the tumour completely disappeared, leaving an area of retinal pigment epithelial and choroidal atrophy. Total decalcification of the choroidal osteoma was demonstrated by ultrasonography. 