Differential diagnosis of anterior chamber cysts with ultrasound biomicroscopy: ciliary body medulloepithelioma

. Purpose:  To describe a case with motile cyst in the anterior chamber in the right eye of a 7‐year‐old boy.Methods:  The right eye's visual acuity was 20/50. Intraocular pressure was 59 mmHg. Slit‐lamp examination showed prominent rubeosis iridis and a grey‐white mass floating freely in the anterior chamber. Ultrasound biomicroscopy revealed a cystic mass in the anterior chamber. A diagnostic cyclectomy with removal of the anterior chamber cyst was performed. Histopathology of the anterior chamber lesion showed an intact cyst composed of medullary epithelial cells. Medulloepithelioma with malignant criteria was diagnosed and the eye was enucleated.Results:  Pathology demonstrated an medulloepithelioma with a few mitotic figures and nuclear pleomorphisms within the ciliary body. The patient was followed for 8 months without any metastasis in the orbit or elsewhere.Conclusion:  Intraocular medulloepithelioma is a rare embryonic benign or malignant neoplasm typically diagnosed in the first decade of life as a ciliary body mass. A dislodged, free‐floating anterior chamber cyst associated with neovascular glaucoma is typical of medulloepithelioma in children. This unique presentation should be differentiated from congenital iris epithelial, post‐traumatic, epithelial, parasitic and neoplastic cysts. Ultrasound biomicroscopy is useful for analysing the structure of the anterior segment mass. Ciliary body medulloepithelioma is characterized by echogenic mass heterogeneity and an irregular surface containing multiple cystic cavities. Lack of glial differentiation may predict a better clinical outcome in primary neuroectodermal brain tumours.