Adenoma of the nonpigmented ciliary epithelium mimicking a malignant melanoma of the iris.

Adenomas of the nonpigmented ciliary epithelium are rare tumors and are difficult to differentiate from amelanotic malignant melanomas of the ciliary body. We describe a 62-year-old woman with a nonpigmented, vascularized iris tumor with small satellites involving the anterior chamber angle. Clinically, an amelanotic, tapioca, malignant melanoma of the iris was suggested although the blood-aqueous barrier was intact. A block excision of 7.5 mm, a tectonic corneoscleral graft, and a simultaneous extracapsular cataract extraction with implantation of a posterior chamber lens were performed. Histopathologic and electron microscopic studies revealed an adenoma of the nonpigmented ciliary epithelium. Postoperative visual acuity was 20/40 OD after 6 weeks. An adenoma of the nonpigmented ciliary epithelium may mimic an amelanotic malignant melanoma of the iris and should be considered in its differential diagnosis.