Intraocular medulloepithelioma

Intraocular medulloepithelioma, also known as diktyoma, is a rare embryonal neoplasm arising from the nonpigmented ciliary epithelium of the eye. This tumor originates from the medullary epithelium, which is the primitive neuroepithelial tissue that normally gives rise to structures of the eye during embryonic development. It is the most common tumor of the ciliary body in children and is typically diagnosed in early childhood, usually before the age of 10 years. Intraocular medulloepithelioma can be classified as benign (nonteratoid or teratoid) or malignant (nonteratoid or teratoid). Teratoid variants contain heteroplastic elements such as cartilage, brain tissue, or skeletal muscle. Key clinical features include a visible mass in the ciliary body region, decreased vision, leukocoria (white pupillary reflex), pain, glaucoma, lens subluxation or cataract, and neovascularization of the iris. The tumor may also present with a characteristic cyst or multiple cysts within the anterior segment of the eye. In some cases, the tumor can be associated with persistent hyperplastic primary vitreous or other developmental ocular anomalies. Rarely, intraocular medulloepithelioma has been reported in association with pleuropulmonary blastoma familial tumor and dysplasia syndrome linked to DICER1 mutations. Treatment depends on the size and extent of the tumor. Small, localized tumors may be managed with local resection (iridocyclectomy or partial lamellar sclerouvectomy), plaque brachytherapy, or cryotherapy. However, enucleation (surgical removal of the eye) remains the most common treatment, particularly for larger tumors or those with secondary complications such as glaucoma or extensive intraocular involvement. Malignant variants carry a risk of local invasion and, rarely, distant metastasis. Early diagnosis and treatment are critical to preserving vision when possible and preventing extraocular spread. Prognosis is generally favorable when the tumor is confined to the eye, but outcomes worsen significantly with extraocular extension.

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