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Progressive Growth of Benign Adenoma of the Pigment Epithelium of the Ciliary Body
Arch Ophthalmol. 2001;119:1859-1861.
INTRODUCTION
A 77-year-old woman underwent iridocyclectomy for a progressively enlarging black mass that apparently originated in the ciliary body and secondarily invaded the iris of her pseudophakic left eye. At the time of surgery, the tumor was adherent to the intraocular lens, which was removed along with the mass. Histopathologically, the tumor was composed of islands and cords of benign pigment epithelial cells that were separated by vascularized fibrous connective tissue. The diagnosis was adenoma of the ciliary body pigment epithelium with secondary invasion of the iris. This case underscores the fact that benign intraocular tumors can show dramatic enlargement without undergoing malignant transformation.
The pigment epithelial layers of the eye often undergo reactive hyperplasia but true neoplasia of ocular pigment epithelia is rare.1-4 On occasion, however, true neoplasms can develop from the pigment epithelia of the iris, ciliary body, and retina.5-7 Tumors of the pigment epithelium generally are benign or low-grade malignancies and have no known tendency to metastasize. However, they can grow slowly and can be locally invasive.5-7 We report a clinicopathologic correlation of an adenoma of the ciliary body pigment epithelium that secondarily invaded the iris and developed into a sizable intraocular mass.
Report of a Case
In 1993, a 70-year-old woman was found on routine ocular examination to have an early cataract in her left eye. At that time, her irides were normal and no pigmented lesions were noted. In 1995, the cataract had progressed and a small pigmented lesion was first noticed in her left iris. This was interpreted as a melanocytic nevus. In 1996, the cataract had shown further progression and successful cataract extraction with placement of a posterior chamber intraocular lens was performed. Two years later, the iris lesion had shown no convincing change, but suspicion of possible melanoma prompted referral to the oncology service.
At the time of our initial evaluation in 1997, the corrected visual acuity was 20/20 OD (phakic eye) and 20/20 OS (pseudophakic eye). Intraocular pressure readings were normal. In the nasal aspect of the left iris was a black lesion that spared the pupillary margin and extended to involve the base of the iris between the 8:30- and 10-o'clock meridians (Figure 1). The mass appeared to be pushing anteriorly through the iris stroma from the ciliary body but it did not seem to arise from or infiltrate the stroma. Gonioscopy showed that the lesion obscured a view of the angle structures and there was fine pigment dusting in the angle inferiorly. Ultrasound biomicroscopy results revealed ciliary body thickening by the mass and transillumination disclosed a shadow that extended across the pars plicata for 1 mm into the pars plana. The favored diagnosis was adenoma of the ciliary body pigment epithelium with secondary extension through the iris. Because of her age and good visual acuity, it was elected to continue to follow the patient conservatively.
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Figure 1. In 1997, the iris component of the lesion appeared as a black mass in the nasal aspect of the iris.
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In 1998, the lesion was first noted to be displacing the intraocular lens. In 1999, the patient's visual acuity had decreased to 20/40 OS and the intraocular lens appeared to be covered by fibrous tissue in the quadrant of the tumor. An episcleral sentinel blood vessel had developed over the tumor and the angle pigmentation inferiorly had become denser. By 2000, the iris component of the lesion had become larger (Figure 2) and ultrasonography showed the ciliary body component of the lesion to be 6 mm thick. With transillumination, the lesion measured 7 x 7 mm in diameter and extended more posteriorly into the pars plana, almost reaching the ora serrata.
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Figure 2. In 2000, the iris component of the lesion was slightly larger. Transillumination and ultrasonography results revealed more pronounced ciliary body involvement posteriorly. The pupil has been dilated pharmacologically.
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Because of the progressive enlargement, the mass was resected by a partial lamellar iridogoniocyclochoroidectomy.8 Firm adherence of the mass to the intraocular lens made them inseparable, necessitating removal of the lens along with the tumor. Postoperatively, there was diffuse vitreous hemorrhage, which slowly resolved during 3 months without the need for a vitrectomy.
Grossly, the black lesion had clear scleral margins. The mass partially encompassed the lens capsular bag, which contained an intraocular lens (Figure 3). Microscopically, the specimen consisted of a lamella of sclera on which rested a pigmented tumor that was passing through the thinned iris (Figure 4). The mass was composed of nests, cords, and islands of intensely pigmented epithelial cells that were separated by prominent septa of vascularized fibrous connective tissue (Figure 5). The cords were solid without evidence of duct formation. The melanin granules in the cytoplasm were large and generally spherical in configuration, resembling those seen in the normal pigment epithelium. Bleached sections showed that the tumor nuclei were generally round or oval with relatively well-dispersed chromatin and small to mildly conspicuous nucleoli (Figure 6). The nuclei were only mildly pleomorphic and only 2 mitotic figures were counted in 40 high-power fields. The posterior surgical margin was free of tumor. Fibrous tissue encompassed a groove in the tumor that contained lens cortical and capsular remnants and a space that was occupied by the intraocular lens haptic in vivo. This was surrounded by capsular fibrosis. There was mild invasion of the ciliary body stroma by the tumor. The final diagnosis was adenoma of the ciliary body pigment epithelium with secondary iris invasion.
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Figure 3. Gross appearance of the resected lesion shows the black mass (to the left) with a sclera base (bottom). There is a firm attachment of the black mass to the intraocular lens (to the left).
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Figure 4. Pigmented mass with a section of normal iris adjacent to the lesion (hematoxylin-eosin; original magnification x10).
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Figure 5. The tumor is composed of islands and cords of deeply pigmented epithelial cells with connective tissue stroma (hematoxylin-eosin; original magnification x200).
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Figure 6. Bleached section showing bland cells with uniform nuclei (bleached, hematoxylin-eosin; original magnification x200).
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Comment
Tumors of the ciliary body pigment epithelium are rare.6, 9-13 Until recently, they were often misdiagnosed clinically as malignant melanoma. In our case, the diagnosis was suspected clinically because of the black color of the lesion. Tumors of the pigment epithelium traditionally have been considered to be relatively dormant but a recent study revealed that those in the ciliary body can cause vitreous hemorrhage, subluxation of the lens, and secondary cataract,6 and that those of the retinal pigment epithelium can be locally invasive and cause exudative retinal detachment.7 Conversely, tumors of the iris pigment epithelium tend to be more stationary and are less likely to exhibit local invasion. In a clinical series of 20 consecutive cases of adenoma of the iris pigment epithelium, only 2 required surgical removal and 18 remained stationary during the course of follow up.5 The tumor in our patient was initially suspected be an iris lesion but detailed examination suggested that it probably originated in the pigment epithelium of the ciliary body. Documented growth of the tumor prompted removal and the diagnosis was confirmed histopathologically.
A remarkable histopathologic feature of the tumor reported here is that it was composed predominantly of solid cords and tubules of tumor cells. These findings are more consistent with reported cases of adenomas of the iris pigment epithelium.5 In contrast, tumors that arise from the ciliary body pigment epithelium are usually characterized by numerous clear vacuoles and have less connective tissue stroma.6 The tumor in our patient lacked such vacuoles. From a clinical standpoint, however, the tumor appeared to originate in the ciliary body and to secondarily invade the iris.
The tumor reported here showed progressive enlargement, secondarily invaded the iris, induced the development of a sentinel blood vessel, and displaced and partially adhered to the intraocular lens. Physicians should be aware that progressive growth of a ciliary body or iris mass does not necessarily imply malignant transformation. Ancillary measures such as gonioscopy, transillumination, and ultrasound biomicroscopy are often necessary to determine the size and extent of a ciliary body mass. Recognition of the characteristic features of adenoma of the ciliary body pigment epithelium should facilitate the diagnosis of this unusual tumor.
AUTHOR INFORMATION
This research was supported by the Eye Tumor Research Foundation, Philadelphia, the Award of Merit in Retina Research, Houston, Tex (Dr J. A. Shields), the Macula Foundation, New York, NY (Dr C. L. Shields), and by the Noel T. and Sara L. Simmonds Endowment for Ophthalmic Pathology, Wills Eye Hospital, Philadelphia (Dr Eagle).
We thank Anthony LaTessa, MD, and Richard A. Frio, OD, for their help in the management of the patient.
Jerry A. Shields, MD;
Ralph C. Eagle, Jr, MD;
Carol L. Shields, MD;
Arun D. Singh, MD
Philadelphia, Pa
Paul F. Torrisi, MD
Syracuse, NY
Corresponding author and reprints: Jerry A. Shields, MD, Oncology Service, Wills Eye Hospital, 900 Walnut St, Philadelphia, PA 19107.
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SECTION EDITOR: W. RICHARD GREEN, MD
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