PSEUDOMELANOCYTOMA AT THE OPTIC NERVEHEAD: AN ADENOMA OF THE RETINAL PIGMENT EPITHELIUM

Analysis of clinical features of RPE adenoma

PURPOSE

This study aims to evaluate the clinical features of adenoma of the retinal pigment epithelium (RPE) and eye-sparing treatment for it.

METHODS

The patients underwent measurement of visual acuity and intraocular pressure, slit-lamp examination, ophthalmoscopy, fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA), color Doppler imaging (CDI), and magnetic resonance imaging (MRI). The tumors were endoresected and studied histopathologically.

RESULTS

Of the 16 Asian patients, 15 had RPE adenoma and 1 had RPE adenocarcinoma. Visual acuity decreased in three cases, mainly due to the macular detachment. All tumors were solitary and unilateral and measured from 1.7 × 3.2 × 2.4 to 9.3 × 8.0 × 6.6 mm³. The tumor was located in the macular area in 2 patients, in the juxtapapillary area in 1 patient, and in the peripheral fundus in 13 patients. The tumors were yellow-pink in 3 patients and brown in 13 patients. The tumors showed hypofluorescence in early stage and mottled hyperfluorescence with prominent leakage in late stage on fluorescein angiography. CDI demonstrated arterial blood signals within tumor, and MRI demonstrated hyperintensity and hypointensity in the T1- and T2-weighted images, respectively. The tumors were positive for S-100, neuron-specific enolase (NSE), CK, epithelial membrane antigen (EMA), and vimentin; occasionally positive for melanin-A; and usually negative for melanoma-specific antigen HMB45 and synaptophysin (Syn). The endoresection surgery was performed in all 16 patients by the microinvasive vitrectomy for the excision of intraocular tumors and reconstruction of the eyeball. The follow-up time was 1.5-13 years (mean, 5 years). No tumor recurrence occurred, and the retina remained attached in 16 eyes.

CONCLUSIONS

RPE-derived adenomas are rare and difficult to diagnose clinically. Local resection by the mircoinvasive vitrectomy is a feasible alternative treatment for RPE adenoma.

Adenoma and Adenocarcinoma of the Retinal Pigment Epithelium: A Review of 51 Consecutive Patients

PURPOSE

To describe the clinical and imaging characteristics, pathologic features, and management options of retinal pigment epithelium (RPE) adenoma/adenocarcinoma.

DESIGN

Retrospective case series.

PARTICIPANTS

Fifty-one patients with RPE adenoma/adenocarcinoma.

METHODS

Treatment options for the patients included observation, partial lamellar sclerouvectomy (PLSU), enucleation, and others.

MAIN OUTCOME MEASURES

Factors related to visual acuity (VA) outcomes (>2 Snellen lines loss, poor final VA [≤20/200], good final vision [≥20/40]), tumor growth, and need for enucleation.

RESULTS

The mean patient age at diagnosis was 51 years, and the majority of patients were white (40/51, 78%) and female (34/51, 67%). Primary management included observation (29/51, 57%), PLSU (9/51, 18%), enucleation (4/51, 8%), or others (9/51, 18%). Outcomes revealed decreased VA (10/32, 31%), poor final VA (17/32, 53%), good final VA (11/32, 34%), tumor growth (12/25, 48%), and need for enucleation (7/51, 14%). By multivariable analysis, features predictive of decreased VA included increasing baseline tumor thickness (P = 0.01) and presence of vitreous hemorrhage (P = 0.05). Factors predictive of poor final VA included presence of exudative retinal detachment (P = 0.004), baseline VA 20/50 to 20/150 (P = 0.008), and baseline VA ≤20/200 (P = 0.01). Absence of feeding and/or draining vessel was predictive of good VA (P = 0.004). Tumor growth was associated with multiple treatments (P = 0.02). Increased tumor thickness (P = 0.03) and presence of exudative retinal detachment (P = 0.01) were predictive of enucleation.

CONCLUSION

RPE adenoma/adenocarcinoma can simulate choroidal melanoma. Greater tumor thickness, vitreous hemorrhage, exudative retinal detachment, and poor baseline VA predict worse visual outcome and greater risk for enucleation.

A clinically challenging diagnosis of adenoma of the retinal pigment epithelium presenting with clinical features of choroidal hemangioma

BACKGROUND

Adenoma of the retinal pigment epithelium (RPE) is a rare intraocular tumor that can simulate other pigmented tumors such as choroidal melanoma. We report a case of non-pigmented adenoma of the RPE initially diagnosed as choroidal hemangioma.

CASE REPORT

A 42-year-old woman presented to Kurume University Hospital in November 1992 with an orange-yellow tumor nasal to the optic disc in the left fundus. The tumor was 9.0 × 9.0 mm in diameter, 6.0 mm thick, and was characterized by high intensity on T1-weighted magnetic resonance imaging (MRI), low intensity on T2-weighted MRI, and enhancement on gadolinium MRI. Fluorescein angiography revealed early hypofluorescence and late hyperfluorescence of the tumor and retinal feeder vessels. By April 1996, exudate had developed around the tumor margins. The patient was treated with external beam radiation therapy (20 Gy) in July 1996, but the tumor did not diminish in size. Subsequently, she developed extensive loss of vision due to total retinal detachment. Accordingly, her left eye was enucleated in June 2005 because of severe ocular pain due to absolute glaucoma. Histopathological examination indicated that the tumor was contiguous with the normal surrounding RPE and was composed of cords and tubules of mostly non-pigmented spindle-shaped cells with round to oval nuclei and a small amount of cytoplasm containing melanin granules. The tumor cells were immunoreactive for vimentin, S-100 protein, and cytokeratin 18. The final diagnosis was adenoma of the RPE.

CONCLUSION

Adenoma of the retinal pigment epithelium may be associated with incompetent vessels leading to serous retinal detachment and extensive visual loss, and may exhibit clinical characteristics similar to choroidal hemangioma.

Pigmented uveal tumours in a transgenic mouse model

AIMS/BACKGROUND

The authors have developed transgenic mouse strains at the Arizona Cancer Center using a tyrosinase promoter to target expression of the mutated T24 Ha-ras gene in melanin producing cells. Histopathology and electron microscopy (EM) were performed to characterise the intraocular tumours observed phenotypically.

METHODS

Transgenic TPras mice (n = 8) and normal, age matched control mice (n = 6) were sacrificed at 3 weeks, 6 weeks, 7 weeks, 4 months, 5 months, 9 months, and 11 months. Six were processed in formalin for light microscopic examination and eight in a glutaraldehyde/formalin solution for electron microscopic examination.

RESULTS

Six of the TPras mice were found to have bilateral pigmented melanocytic/RPE proliferations of the uveal tract. The cytological characteristics of the tumours included low nuclear to cytoplasmic ratios (N:C ratios), bland nuclei, and abundant intracytoplasmic melanin. By EM two populations of cells were identified, including spindle-shaped cells with round to oval melanin granules and cuboidal cells with apically located, cigar-shaped, melanin granules, and basement membrane formation. A 3 week and an 11 month old TPras mouse had a higher grade, bilateral, melanocytic proliferation of the uveal tract which, although not metastatic, was morphologically melanoma. Cytological features included increased N:C ratios, nuclear pleomorphism, and prominent nucleoli. The uveal tract was normal in both eyes in all of the control animals.

CONCLUSION

Pigmented intraocular tumours developed in transgenic strains of mice that express a mutated Ha-ras gene in melanin producing cells. The morphology was most consistent with a melanoma in two of the mice and a benign melanocytic/RPE proliferation in the remaining mice.

Pigmented adenoma of the optic nerve head simulating a melanocytoma

PURPOSE

The purpose of this report is to describe a clinicopathologic correlation of an unusual pigmented tumor of the optic nerve head, to point out that such a lesion can simulate clinically a melanocytoma of the optic disc, and to discuss the differential diagnosis of pigmented epipapillary lesions.

FINDINGS

Histopathologic studies of the affected eye showed a peculiar pigmented tumor of the optic disc that was compatible with an adenoma arising from the juxtapapillary retinal pigment epithelium.

CONCLUSIONS

Adenoma of the retinal pigment epithelium can closely simulate a melanocytoma of the optic disc. There are some clinical features that may serve to differentiate the two lesions.

Focal congenital anomalies of the retinal pigment epithelium

The terms, 'hamartoma', 'choristoma', 'phacoma' (mother-spot), and 'naevus', are used to describe benign developmental tumours or placoid lesions. Stedman's Medical Dictionary defines a hamartoma as: 'A focal malformation that resembles a neoplasm grossly and even microscopically, but results from faulty development in an organ; it is composed of an abnormal mixture of tissue elements, or an abnormal proportion of a single element, normally present in that site, which develop and grow at virtually the same rate as normal components, and are not likely to result in compression of the adjacent tissue (in contrast to neoplastic tissue).' A choristoma is defined as 'a mass formed by maldevelopment of tissue of a type not normally found at that site.' Phacoma is defined as, 'a hamartoma found in phacomatosis,' a group of hereditary diseases characterised by hamartomas of multiple tissues. A naevus is a, 'birthmark; a circumscribed malformation of the skin, especially if coloured by hyperpigmentation or increased vascularity; it may be predominantly epidermal, adnexal, melanocytic, vascular, or mesodermal, or a localised overgrowth of melanin-forming cells arising in the skin early in life.' Ophthalmologists have adopted the term to refer to developmental melanocytic lesions of the uveal tract, but heretofore have not used it to describe developmental melanocytic, glial, or vascular lesions of the retina. The purpose of this report is to summarise the author's observations and concepts concerning focal lesions that probably are developmental tumours and placoid lesions composed of either entirely or in part retinal pigment epithelium (RPE). Two of the lesions are tumefactions and may properly be termed 'hamartomas'. Four of the lesions are placoid and might better be described as naevi. Two are composed of hypertrophied RPE cells engorged with melanin granules, one is presumed to be hypertrophied RPE cells filled with a white pigment of unknown nature and one is composed of RPE cells containing no pigment. Three are widely recognised, three others are not.

Pigmented tumor and acute visual loss

A 22-year-old man presents with a history of blurring of vision in his right eye. Ophthalmologic examination reveals a pigmented mass obscuring his optic disc. Two weeks later the patient experienced the apoplectic onset of visual loss to light perception. Discussions center around the presumed diagnosis of melanocytoma of the optic nerve.

Angle closure glaucoma as initial manifestation of melanocytoma of the optic disc

A 44-year-old man had progressive visual loss and pain due to angle-closure glaucoma associated with a papillary pigmented lesion. The eye was enucleated because of intractable pain and the suspicion of a malignant tumor. Histologic and electron microscopic examination of the enucleated eye revealed a partially necrotic melanocytoma of the optic nerve. There was histologic evidence of vaso-occlusive disease within the optic nerve that resulted in ischemic necrosis of the tumor, hypoxic retinopathy and neovascular glaucoma. This report emphasizes that significant complications may occur in otherwise typical intraocular nevi.

Congenital anomalies of the optic disc

Although anomalies affecting the optic nerve head are usually clinically innocuous, they can sometimes cause significant symptoms and lead to visual loss. It is important to be able to recognize even the relatively benign lesions in order to differentiate them from other more threatening lesions or disease processes which they may clinically resemble. An awareness of the clinical appearance of disc anomalies is especially important in the differential diagnosis of optic nerve glaucomatous changes. Some anomalies cause various types of visual field loss which, if the actual disc lesion is not recognized, may lead to unnecessary neurologic evaluation or even to intracranial surgery. The optic nerve changes in acquired myopia and in the congenital tilted disc syndrome should be clearly defined and differentiated: high (pathologic) myopia may be highly progressive with many dangerous secondary sequelae, while the latter anomaly is stationary. Finally, there is a group of conditions, collectively termed "elevated anomalies of the disc," which must be considered in the differential diagnosis of papilledema and potentially dangerous intraocular tumors, particularly retinoblastoma. This review provides a clinicopathologic correlation comparing the characteristics of the normal optic disc to those of the most important congenital anomalies of the disc.

Tumors of the optic nerve

This is a review of primary and secondary tumors of the optic nerve. The emphasis is an optic nerve gliomas and meningiomas. Optic nerve gliomas are slowly growing astrocytic neoplasms of the anterior visual pathways, the majority of which occur within the first two decades of life, with equal sex incidence in about 1 of 200,000 patients presenting with eye complaints. The incidence is greater in neurofibromatosis. The typical presentation is visual impairment in a verbal pre-school child with optic canal enlargement and optic atrophy. An intraorbital location of the tumor leads to axial, irreducible, non-pulsatile proptosis. An intracranial location may disturb hypothalamic and pituitary function and produce hydrocephalus. Ocular findings may also include limited motility on a mechanical-restrictive basis, a pupillary relative afferent defect, nystagmus, and variable, non-specific visual field defects. Roentgenographic studies may show concentric unilateral enlargement of the optic canal with preservation of a well corticated margin, a fossa under the anterior clinoid process in continuity with the optic canal ('J'-shaped sella), and findings of increased intracranial pressure. On pathologic examination the tumor is a smooth, fusiform, intradural enlargement of the optic nerve. Histologically there is proliferation of elongated (pilocytic) astrocytes in reticulated patterns with intervening microcystic spaces containing mucosubstance and surrounding reactive hyperplasia of the arachnoid. Mitoses are not found. The diagnosis is clinical X-ray studies and brain scan should be performed. The differential diagnosis is that of unilateral proptosis in a child and includes acute ethmoiditis, hyperthyrobidism, craniostenosis, other neoplasms, Hand-Schuller-Christian disease, and orbital hemorrhage due to trauma. Surgical resection is performed in cases with unilateral optic nerve involvement, the surgical approach being determined by tumor location. Bilateral or chiasmal cases are treated with radiotherapy when progression occurs. Malignant optic nerve gliomas and optic nerve hyperplasia are also discussed. Optic nerve meningiomas arise from the nerve sheath and are to be distinguished from orbital meningiomas arising from ectopic arachnoidal cells or those secondarily involving the orbit by extension from adjacent sites. Up to 80% of orbital meningiomas occur in females, in two age peaks, 25% in the first decade, and the rest in the 5th decade. Meningiomas present with visual loss and may produce proptosis, papilledema and/or optic atrophy, retinal striae, opticociliary shunts, limitation of extra-ocular movements, and lid edema, Signs of von Recklinghausen's disease should be sought. X-rays are the mainstay of diagnosis. Orbital meningiomas are composed of cells in sheets or in whorls with some spindle shaped cells. Calcifications are typical. Usually the dura is penetrated and the orbit invaded. Primary orbital meningiomas are locally infiltrating but do not metastasize. Complete local excision en bloc is recommended...

Tumours of the retinal pigment epithelium

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