Phakomatous choristoma of the orbit.

Phakomatous choristoma is a rare adnexal congenital tumor of lenticular anlage. The authors performed a standard orbital tomography of the orbits for the evaluation of a mass that was palpable in the left lower eyelid of a 3-month-old boy. Hematoxylin-eosin, special stainings and immunohistochemistry were performed on the excised mass. The histopathological and immunohistochemical findings confirmed the diagnosis of phakomatous choristoma. The CT scans showed that the mass was located in the orbit. Even though phakomatous choristoma is usually reported as a lower eyelid lesion, the orbital localization offers a better explanation for the chronological embryonic origin of this rare pediatric tumor.