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Adenoma of the Retinal Pigment Epithelium Simulating a Juxtapapillary Choroidal Neovascular Membrane
Jerry A. Shields, MD;
Miguel Materin, MD;
Carol L. Shields, MD;
Ralph C. Eagle, Jr, MD
Arch Ophthalmol. 2001;119:289-292.
ABSTRACT
We report a case of an adenoma of the retinal pigment epithelium that
clinically simulated a juxtapapillary choroidal neovascular membrane in a
60-year-old man. Fluorescein angiography supported the diagnosis of a juxtapapillary
choroidal neovascular membrane in his left eye. After 13 years the lesion
become slightly pigmented and the optic disc became swollen. The possibility
of choroidal melanoma with optic disc invasion was considered, and the eye
was enucleated. The lesion proved histopathologically to be an adenoma of
the retinal pigment epithelium.
INTRODUCTION
Choroidal neovascular membrane (CNVM) is a common condition that has
typical clinical and fluorescein angiographic features. It usually occurs
in older patients as a variant of age-related macular degeneration. Sometimes
a CNVM can develop in a juxtapapillary location, usually on the temporal margin
of the optic disc.1 Adenoma of retinal pigment
epithelium (RPE) is a rare tumor that often simulates a choroidal melanoma.2-3 It generally occurs as an abruptly
elevated, pigmented mass in an extramacular location and does not resemble
a CNVM. Rarely, an adenoma of the RPE can be clinically nonpigmented.3 We report a case of clinicopathologic correlation
of an atypical juxtapapillary adenoma of the RPE that simulated a CNVM and
was followed for 12 years with that diagnosis.
REPORT OF A CASE
In 1986, a 60-year-old man developed the gradual onset of painless visual
impairment in his left eye. He was seen by a retinal specialist and was treated
with laser photocoagulation for a presumed CNVM on the temporal margin of
the optic disc. The lesion apparently remained stable. The patient was first
examined by one of us (M.M.) in June 1998. The right eye was entirely normal.
The visual acuity in the affected left eye was 6/9, and fundus examination
disclosed a yellow-pink placoid lesion temporal to the optic disc measuring
3 x 3 x 1 mm. A crescent-shaped subretinal hemorrhage was present
on the temporal margin of the lesion, with scattered cells in the overlying
vitreous (Figure 1). A rim of localized
subretinal fluid was present on the temporal and inferior margins of the mass.
Fluorescein angiography showed early hyperfluorescence and late intense leakage
compatible with a CNVM. No further treatment was given.
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Figure 1. Fundus photograph (June 1998).
Temporal to the optic disc is a deep yellow-pink lesion with a crescent-shaped
hemorrhage on its temporal margin, highly suggestive of a choroidal neovascular
membrane. The view is slightly hazy because of overlying vitreous cells.
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At the time of follow-up examination in June 1999, his visual acuity
was finger counting at 2 ft, the lesion was thicker and had become slightly
pigmented, and the optic nerve was slightly more hyperemic (Figure 2). Fluorescein angiography showed early, lacy hyperfluorescence
of the lesion and late leakage into the surrounding retina (Figure 3). B-scan ultrasonography demonstrated an elevated mass
measuring 2.3 mm in thickness with acoustic hollowness (Figure 4). A-scan ultrasonography showed a solid lesion with medium
internal reflectivity. Orbital magnetic resonance imaging demonstrated an
enhancing mass near the optic disc but no demonstrable extension posteriorly
into the optic nerve.
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Figure 2. Fundus photograph (June 1999).
The lesion is slightly thicker and slightly pigmented, and the disc is hyperemic.
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Figure 3. Fluorescein angiograms. A, Laminar
venous phase showing early, lacy hyperfluorescence of the lesion. B, Late
phase demonstrating leakage from the subretinal lesion and late staining of
the adjacent subretinal fluid.
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Figure 4. B-scan ultrasonogram showing the
mass to have slight acoustic hollowness.
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The patient was informed of the possibility of a small, growing choroidal
melanoma with optic disc invasion, and he was given the options of observation
or enucleation. Because of the possibility of melanoma in an eye with minimal
visions, he elected to have enucleation. This was done without complication,
and the patient had an uneventful postoperative course.
PATHOLOGICAL FINDINGS
Gross and microscopic examination of the sectioned eye revealed an ovoid
mass that measured 4 x 4 x 3 mm, which covered the temporal margin
of the optic disc (Figure 5). Microscopically,
the tumor was composed of cords of amelanotic cells with slightly pleomorphic
round-to-oval nuclei and fairly prominent nucleoli (Figure 6). The tumor cells rested on periodic acid–Schiff–positive
septa (Figure 7). Rare mitotic figures
were evident. At its apex, tongues of tumor cells invaded the overlying sensory
retina. There was a shallow retinal detachment adjacent to the tumor. The
nearby retina also contained pools of proteinaceous fluid in the outer plexiform
layer, consistent with hard exudates.
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Figure 5. Low-magnification photomicrograph
showing elevated cellular, eosinophilic mass, compressing the optic nerve
(to the right) (hematoxylin-eosin, original magnification x10).
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Figure 6. The amelanotic tumor cells show
cordlike arrangement, resembling epithelium. The nuclei are slightly pleomorphic,
and the nucleoli are fairly prominent (hematoxylin-eosin, original magnification
x200).
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Figure 7. Periodic acid–Schiff preparation
demonstrating abundant basement membrane compatible with an epithelial tumor
(original magnification x200).
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The tumor cells showed intense immunoreactivity for vimentin and cytokeratin
marker CAM 5.2 (Figure 8). There
was mild immunoreactivity to S100 protein and cytokeratin marker AE3. Melanoma-specific
antigen HMB 45 was nonreactive. Despite the mild cytologic atypia (pleomorphic
nuclei with prominent nucleoli), the favored diagnosis by 2 ophthalmic pathologists
was pleomorphic adenoma of the RPE.
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Figure 8. Tumor cells show cytoplasmic immunoreactivity
to keratin marker CAM 5.2 consistent with an epithelial tumor (peroxidase-antiperoxidase,
original magnification x150).
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COMMENT
Adenoma of the RPE is a rare intraocular neoplasm that can resemble
a choroidal melanoma.2-3 In a
recently reported series of tumors of the RPE,3
the authors outlined the salient features that help differentiate these tumors
from choroidal melanoma. Tumors of the RPE usually are dark black, often invade
the sensory retina, develop a dilated retinal feeding artery and draining
vein, and cause exudative retinopathy.1-2
Adenoma of the RPE can sometimes arise in a juxtapapillary location, where
it can simulate a melanoma or melanocytoma.3-5
In addition, few clinicians are aware of the fact that a neoplasm of the RPE
can be clinically amelanotic.6 Even when adenoma
of the RPE is amelanotic, it still appears as an elevated nodule, and its
tumorous proportions are generally obvious.6
The tumor reported herein closely simulated a juxtapapillary CNVM clinically
and angiographically. When it enlarged and compressed the optic disc, the
possibility of a small juxtapapillary choroidal melanoma with optic disc invasion
was considered, and the eye was enucleated. The diagnosis of adenoma of RPE
was not suspected clinically. In retrospect, the retinal hemorrhage and exudation
were subtle clues to the underlying diagnosis, since such changes are frequently
associated with adenoma of the RPE but would be unlikely with a small melanoma.
Neoplasms of the RPE have not been known to metastasize. However, they can
be locally aggressive by producing exudative retinal detachment, vitreous
hemorrhage, cataract, and orbital extension.7
It is feasible that such advanced tumors could exhibit metastasis, but, to
our knowledge, this has not been convincingly documented.
The histopathologic findings in our case were consistent with other
reported tumors of the RPE. This neoplasm can superficially resemble an epithelioid
cell choroidal melanoma. However, there are several histologic features that
help distinguish RPE adenoma from epithelioid cell melanoma. The cells constituting
RPE adenomas are located on the inner surface of Bruch's membrane and do not
involve the choroidal stroma, where melanoma resides. The epithelial cells,
which may be pigmented or amelanotic, often are arranged in linear segments
on the surface of periodic acid–Schiff–positive connective tissue
septa or may form papillary or tubular patterns. Immunohistochemical analysis
also is useful in confirming the diagnosis. Tumors of the RPE are nonreactive
for melanoma marker HMB 45 but usually show immunoreactivity for cytokeratin
markers such as CAM 5.2. Care must be taken in the analysis of immunohistochemical
data, however, because uveal melanoma cells with the so-called interconverted
phenotype can coexpress cytokeratins 8 and 18 and vimentin.8
In summary, a lesion that appeared for more than 12 years to be a juxtapapillary
CNVM was found histopathologically to be a pleomorphic adenoma of the RPE.
It is possible that other similar cases may have been diagnosed as CNVMs and
were either observed or treated with laser photocoagulation. Ophthalmologists
should be aware that neoplasms of the RPE can resemble a CNVM.
AUTHOR INFORMATION
Accepted for publication June 16, 2000.
This study was supported by the Eye Tumor Research Foundation, Philadelphia,
Pa; the Award of Merit in Retina Research, Houston, Tex (Dr J. A. Shields);
the Macula Foundation, New York, NY (Dr C. L. Shields); and the Noel T. Sara
L. Simmonds Endowment for Ophthalmic Pathology, Wills Eye Hospital, Philadelphia,
Pa (Dr Eagle).
Ramon L. Font, MD, provided an opinion on the pathology of this case.
Corresponding author and reprints: Jerry A. Shields, MD, Oncology
Service, Wills Eye Hospital, 900 Walnut St, Philadelphia, PA 19107.
From the Oncology Service (Drs J. A. Shields, Materin, and C. L. Shields)
and Department of Pathology (Dr Eagle), Wills Eye Hospital, Thomas Jefferson
University, Philadelphia, Pa.
REFERENCES
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1. Gass JDM. Idiopathic choroidal neovascularization, juxtapapillary type. In: Gass JDM. Stereoscopic Atlas of Macular Diseases. 4th ed. St Louis, Mo: CV Mosby Co; 1997:248.
2. Shields JA, Shields CL. Tumors of the retinal pigment epithelium. In: Shields JA, Shields CL. Atlas of Intraocular
Tumors. Philadelphia, Pa: Lippincott Williams & Wilkins; 1999:288-292.
3. Shields JA, Shields CL, Gunduz K, Eagle RC Jr. Neoplasms of the retinal pigment epithelium: The 1998 Albert Ruedemann
Sr Memorial Lecture, part 2. Arch Ophthalmol. 1999;117:601-608.
FREE FULL TEXT
4. Shields JA, Eagle RC Jr, Shields CL, De Potter P. Pigmented adenoma of the optic nerve head simulating a melanocytoma. Ophthalmology. 1992;99:1705-1708.
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5. Loose IA, Jampol LM, O'Grady R. Pigmented adenoma mimicking a juxtapapillary melanoma. Arch Ophthalmol. 1999;117:120-122.
FREE FULL TEXT
6. Shields JA, Eagle RC Jr, Barr CC, Shields CL, Jones DE. Adenocarcinoma of the retinal pigment epithelium arising from a juxtapapillary
histoplasmosis scar. Arch Ophthalmol. 1994;112:650-653.
ABSTRACT
7. Edelstein C, Shields CL, Shields JA, Eagle RC Jr. Presumed adenocarcinoma of the retinal pigment epithelium in a blind
eye with a staphyloma. Arch Ophthalmol. 1998;116:525-528.
FREE FULL TEXT
8. Henrix MJC, Seftor EA, Seftor REB, et al. Biologic determinants of uveal melanoma metastatic phenotype: role
of intermediate filaments as predictive markers. Lab Invest. 1998;78:153-163.
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