Retinal Pigment Epithelial (RPE) Hypertrophy

Description

Note the flat, black well circumscribed lesion with areas of retinal pigment epithelial atrophy.

The retinal pigment epithelium (RPE) is a pigmented layer of the retina which can be thicker than normal at birth (congenital) or may thicken later in life. Areas of retinal pigment epithelial (RPE) hypertrophy usually do not cause symptoms. They are typically found during routine eye examinations.

There are two main types:
Congenital retinal pigment epithelial hypertrophy (CHRPE) is usually found before patients reach 30 years of age. They may enlarge with time, but are not commonly associated with malignant transformation. There has been an association made between people with Gardner's Syndrome (familial colonic polyposes) and CHRPE. If your eye care specialist has told you that you have congenital retinal pigment epithelial hypertrophy, it is reasonable to tell your gastroenterologist so that he may recommend the frequency of your screening tests.

This is a case of congenital hypertrophy of the retinal pigment epithelium, "bear-tracks." They too block fluorescence.

Acquired retinal pigment epithelial hypertrophy is typically found later in life. They are typically jet-black to gray, flat, with a halo around its edges. They are variable in size, and may develop lacunae of lightly colored areas of atrophy (see above). These tumors are more commonly found in the peripheral retina where thickness is more difficult to judge by ophthalmoscopy.

This area of retinal pigment epithelial hypertrophy demonstrates a blue hue.

Symptoms

Almost all patients with retinal pigment epithelial hypertrophy do not have symptoms. These pigmented intraocular lesions are found by eye care specialists during dilated examination of the inside of the eye (ophthalmoscopy). Eye tumor specialists can differentiate between retinal pigment epithelial hypertrophy and melanoma by clinical examination (without a biopsy).

Diagnosis

A small area of retinal pigment epithelial hypertrophy. It appears well circumscribed and with areas of relative lucency at the edges.

Retinal pigment epithelial hypertrophy can be diagnosed by ophthalmic examination. This will include a careful history for familial colon disease (polyposes). The eye examination will concentrate on the appearance of the retinal pigment epithelial hypertrophy. These lesions tend to be black or atrophic. They may be surrounded by a halo of less pigmented tissue or exhibit a sharp demarcation line. 

Ultrasonography typically shows that RPE hypertrophy is flat to minimally elevated, normal or slightly hyper-reflective.

Fluorescein angiography of RPE hypertrophy typically demonstrates blockage of fluorescence (except in the areas of atrophy which are hyperfluorescent).

The hypertrophic areas block fluorescence while the choroidal vessels can be visualized within the areas of atrophy. The hypertrophic retinal pigment epithelium continues to be hypofluorescent, while the choroidal vessels leak to form hyperfluorescent areas.

Treatments

Photographic documentation of these lesions is recommended for future comparison. Ultrasonography and fluorescein angiography is typically used to differentiate RPE hypertrophy from uveal melanoma and certain rare intraocular tumors. Serial observation (periodic eye examinations) are recommended.