Rare Histological Type of Adenoma of the Nonpigmented Ciliary Epithelium

We report the rare case of an adenoma of the nonpigmented ciliary epithelium (NPCE). A 67-year-old healthy man presented with a regularly shaped and nonpigmented mass at the iris root of his right eye. His best-corrected visual acuity was 1.5 with normal intraocular pressure. During observation, the size of the tumor remained stable for 1.5 years but then rapidly grew, extending through the iris, and gradually enlarged to the point of compressing the iris. Ultimately, an iridocyclectomy with scleral resection under a lamellar scleral flap was performed. The histopathologic features of the resected tissue were consistent with adenoma of the NPCE. Histopathological analysis showed that the tumor consisted of both tubular and solid components. There were solid lesions inside of the ciliary epithelium and tubular lesions outside. We observed positive immunoreactivity to vimentin and cytokeratin CK (AE1/AE3) and negative reactivity to S-100 and CD68, both rarely associated with adenoma of NPCE. During 1 year of follow-up after the iridocyclectomy, no signs of tumor recurrence were observed.

Distribution of Nidogen in the Murine Eye and Ocular Phenotype of the Nidogen-1 Knockout Mouse

Distribution and lack of nidogen-1, part of numerous basement membranes, were studied in the mouse eye. For that purpose, eyes of C57BL/6 and nidogen-1 knockout mice were stained immunohistochemically for nidogen-1, and intraocular pressure measurements and light- and electron microscopy were used to study the nidogen-1 knockout animals. In normal mice, nidogen-1 was present in many basement membranes, but showed irregularities underneath the corneal epithelium, in Bruch’s membrane and in the iris. Homozygous knockout of nidogen-1 in the mouse showed only mild pathological changes. In the anterior eye segment, small interruptions were noted in the nonpigmented ciliary epithelium without further consequences. In the posterior eye segment, interruptions of the inner limiting membrane led to small retinal ectopias and subsequent changes in the optic nerve. In summary, the knockout of nidogen-1 showed mild but significant morphological changes pointing to the importance of this protein which can in part, but not completely; be replaced by nidogen-2.