Orbital meningoencephalocele manifesting as a conjunctival mass.

Orbital meningoencephalocele is a rare congenital abnormality caused by a defect of the cranio-orbital bones that usually manifests soon after birth as a soft, cystic fullness in the superomedial canthal area with associated exophthalmos. We managed an unusual case of congenital orbital meningoencephalocele that manifested as a cystic conjunctival mass without proptosis or periorbital changes. Preoperative computed tomographic scans failed to demonstrate a bone defect. After suture ligature of the posterior stalk, excision of the lesion yielded an ependymal cyst surrounded by neuroglial and meningeal tissue and filled with cerebrospinal fluid. The patient had normal results of ophthalmic and neurologic examinations after transconjunctival resection of the lesion after three years of follow-up. An orbital approach may be appropriate for a few selected cases in which no bone defect is found on computed tomography. Orbital meningoencephalocele should be included in the differential diagnosis of isolated congenital conjunctival cystic masses.