An epithelioma of the ciliary body.

A 57-year-old woman developed a ciliary body mass which compressed the anterior side of the lens with focal cataract causing the iris to protrude into the anterior chamber. The lesion was removed by a large iridocyclectomy. The mass was classified as an epithelioma of the ciliary body, which was consistent with a benign epithelioma, i.e. an adenoma of the nonpigmented ciliary epithelium. Light and electron microscopic examinations revealed that the tumor cells had characteristics of both the ciliary and iris epithelium, which originated from the neuroectoderm, including abundant cytoplasmic filaments, and pheomelanosomes, and that the gland-like lumen was the pseudoacinous lumen, i.e. invaginated stroma containing the vitreous.