Bilateral choroidal osteoma in three siblings.

Three siblings (a sister and two identical-twin brothers) had bilateral choroidal osteomas. The sister was seen at 11 years of age, and the tumor showed significant growth two years later. The twin brothers' tumors were diagnosed at 9 years of age, and their conditions remained stable over two years except for a new, isolated lesion that occurred in one eye of one brother. The siblings' mother had a yellow mottling situated nasal to the disk in each eye that was similar in appearance to that in one eye of one of the twins. She showed no evidence of calcium on ultrasonography. The appearance of osteomas in three siblings suggests a choristoma as the cause of this tumor.