Imaging features of medulloepithelioma: report of four cases and review of the literature

Intraocular medulloepithelioma is a childhood tumor arising from the nonpigmented primitive ciliary neuroepithelium. Although rarer than retinoblastoma, it remains the second most common primary intraocular neoplasm in children. The rarity of intraocular medulloepithelioma creates the challenge in establishing a clinical diagnosis, and radiologically the tumor is often confused with other intraocular masses. To describe the clinical, imaging and pathological features of intraocular medulloepithelioma with emphasis on the role of imaging to enable its differentiation from more common intraocular pathology. We retrospectively analyzed the clinical, histopathological and imaging data of four children with intraocular medulloepithelioma. All four children had medulloepithelioma arising from the ciliary body. The children were imaged with US (n = 3), MRI (n = 4), whole-body Tc-99m-MDP scintigraphy (n = 2) and CT (n = 1). All four children had enucleation of the involved eye. One tumor was a malignant teratoid variant, two tumors were malignant nonteratoid variants and one was a nonteratoid variant of uncertain malignant potential. None of the tumors had extraocular extension on histopathology or imaging. Two children had associated retinal detachment on US and MRI examinations. All tumors were iso/hyperintense to vitreous on T1-weighted and hypointense on T2-weighted MRI and showed marked contrast enhancement of the solid components. No calcifications were identified on US or CT examinations. Our findings are consistent with previously reported cases of medulloepithelioma. This series emphasizes the roles of various imaging modalities, with pathological correlation, in differentiating the tumor from other ciliary body masses, in detecting tumor extension and in identifying associated ocular complications. In this series we also describe the results of postsurgical follow-up for tumor recurrence.