A 7-year-old boy developed a motile cyst in the anterior chamber of his right eye. Visual acuity was 20/50 and intraocular pressure (IOP) was 59 mmHg. Slit-lamp examination showed prominent rubeosis iridis and a grey-white mass floating freely in the anterior chamber with positive Tyndall light phenomenon (Fig. 1). The rest of the right eye and MRI of the orbit and head were unremarkable.
Ultrasound biomicroscopy (UBM P40; Paradigm Medical Industries, Inc., Salt Lake City, Utah, USA) revealed a cystic mass measuring 1205 µm in diameter located in the anterior chamber (Fig. 2A). Ultrasound biomicroscopy demonstrated a medium-to-high reflective mass at 360-degrees surrounding the entire ciliary body. This mass, with a solid region measuring from 414 µm to 1856 µm in thickness, contained multiple hypoechoic ovoid cystic cavities ranging from 201 µm to 1897 µm in diameter (Fig. 2B−F). The anterior chamber angle was completely closed.
A diagnostic cyclectomy with removal of the anterior chamber cyst was performed. Histopathology of the anterior chamber lesion showed an intact cyst composed of 1–2 cellular layers of medullary epithelial cells (Fig. 3A). The ciliary body biopsy disclosed poorly differentiated neuroepithelial cells and cords that closely resemble the medullary epithelium. A diagnosis of medulloepithelioma with malignant criteria (Shields et al. 1996) was made and the eye was enucleated. Pathology demonstrated an intraocular tumour with a few mitotic figures and nuclear pleomorphisms within the ciliary body. Homer Wright rosettes were prominent (Fig. 3B). Some neoplastic cells were shown to have spread into the posterior chamber and anterior vitreous; however, there was no invasion or extension outside the globe. Immunohistochemistry showed positive staining for neuron-specific enolase protein (NSE) (Fig. 4A) but was negative for glial fibrillary acidic protein (GFAP) (Fig. 4B). The patient was followed for 8 months without any metastasis in the orbit or elsewhere.