Congenital Hypertrophy of RPE (CHRPE) is a benign eye condition often discovered during routine screenings. With specialized care from top retina specialists, you can learn how CHRPE might affect your ocular health and systemic concerns.
Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is a benign, typically asymptomatic pigmented lesion found on the fundus of the eye. This condition is a congenital hamartoma of the retinal pigment epithelium, meaning it originates during eye development and generally does not harm vision. It is an important aspect of retinal evaluations, often discovered incidentally during routine eye examinations by our retina specialists.
This condition appears in three forms—solitary (unifocal), grouped (multifocal), and atypical—with only the atypical type linking to systemic concerns like familial adenomatous polyposis (FAP). Although most CHRPE lesions remain harmless, the atypical variant is a marker for an underlying inherited condition that increases the colon cancer risk later in life. Recognizing CHRPE and understanding its different presentations play a vital role in overall ocular and systemic health identification.
Here’s the thing: understanding CHRPE not only empowers patients with knowledge about their eye health but also serves as an early window into potential systemic issues in rare cases, making regular eye checkups a valuable piece of your preventive health puzzle.
Solitary CHRPE is the most common presentation, appearing as a single, flat, round lesion with distinct pigmentation that can range from light gray to deep black. These lesions usually exhibit smooth or scalloped edges with a clear boundary between the abnormal and the normal retinal pigment epithelium. Typically, solitary CHRPE lesions are found near the equator of the eye, predominantly in the superotemporal quadrant, yet they may be located anywhere in the fundus.
Some key aspects include:
Understanding solitary CHRPE is essential as it helps distinguish this benign finding from other pigmented lesions that might require further evaluation.
Grouped CHRPE, sometimes referred to as the “bear track” appearance due to the clusters resembling animal footprints, consists of several similar lesions arranged together in a cluster. Typically, each group may include up to 30 small lesions, each varying in size from about 100 to 300 micrometers.
These lesions generally share the following characteristics:
The distinct configuration of these lesions contributes to their ease of identification during routine retinal examinations.
Atypical CHRPE represents a distinct subset and is of special concern because of its association with familial adenomatous polyposis (FAP), an autosomal dominant syndrome characterized by the development of numerous colorectal adenomatous polyps. These lesions differ from the benign forms by exhibiting features such as retinal invasion, proliferation of retinal pigment epithelial cells, and accompanying vascular changes.
Notable points regarding atypical CHRPE include:
This type of CHRPE is not just an eye condition—it may serve as an early indicator of FAP. When multiple or bilateral lesions are detected, especially within a family history of polyposis-related cancer, it is a red flag prompting further systemic evaluation. According to recent studies, these lesions are present in approximately 78% of individuals with FAP, underscoring the significance of careful retinal screening.
One of the reassuring aspects of CHRPE is that it is commonly identified during routine eye examinations without affecting vision. Our retina specialists typically spot these lesions during a comprehensive dilated fundus exam. Yet, several diagnostic tools help in documenting and following up on these retinal findings, ensuring that any changes over time are noted.
This imaging modality captures detailed images of the retina and is excellent for documenting the spot’s appearance and monitoring any changes over time.
Recommended as a screening tool in many cases, this technology offers a wide view of the retina, helping in the identification of peripheral lesions.
Due to the high melanin content of CHRPE lesions, they typically show hypoautofluorescence, making autofluorescence imaging a useful adjunct to clinical diagnosis. Areas lacking pigment may still display some autofluorescence, providing additional insights.
These tests reveal that the lesions block the underlying choroidal fluorescence without demonstrating leakage, except in areas with depigmented lacunae or haloes.
OCT helps in visualizing retinal thinning and the loss of photoreceptors over the lesion sites, especially in areas of depigmentation, while also indicating the thickened retinal pigment epithelium.
Although OCT-A has some limitations due to the physical characteristics of the lesions, it remains a better tool than FA or ICGA in visualizing choroidal vasculature.
These diagnostic procedures not only confirm the presence of CHRPE but also help in ruling out other conditions that look similar. Knowing the exact nature of the lesion is essential because it provides a complete picture of eye health and, in some cases, signals the need for further systemic evaluation for conditions like FAP.
The pathology of CHRPE is rooted in its nature as a congenital hamartoma, which means it is a benign overgrowth of cells that normally compose the retinal pigment epithelium. On a microscopic level, most solitary and grouped CHRPE lesions feature a single layer of hypertrophied (enlarged) RPE cells that are densely packed with large, round macromelanosomes—organelles loaded with melanin pigment.
Over time, certain changes can occur within these lesions:
Importantly, while the inner retinal layers, choroid, and choriocapillaris remain unaffected, the specific changes within the RPE highlight the unique nature of CHRPE. For patients, this detailed understanding helps reinforce that the lesions are largely benign, although caution is warranted when systemic associations like FAP come into play.
In the retina, several conditions can mimic the appearance of CHRPE. However, accurate recognition is crucial to avoid misdiagnosis and unnecessary anxiety. Differential diagnoses include choroidal melanoma, choroidal nevus, melanocytoma, and lesions caused by injury or inflammation. Additionally, focal pigmentation due to drug reactions or hyperplasia of the RPE may appear similar during an eye exam.
Another condition that may cause some confusion is congenital grouped albinotic retinal pigment epithelial spots (CGARPES), also known as “polar bear tracks.” These spots are distinct in that they present as multiple, grouped white spots and lack the classic pigmentation seen in CHRPE. While their exact nature remains less understood, the differences in appearance are enough to guide experienced clinicians.
Recognizing these differences is important because it underlines the fact that CHRPE, despite its potentially striking appearance, is usually a benign finding. Our retina specialists rely on the combination of visual inspection and specialized imaging techniques to confidently differentiate CHRPE from more sinister lesions.
For most individuals, the presence of CHRPE does not lead to complications that require active intervention. However, regular monitoring is key. Studies have shown that CHRPE lesions may enlarge in a significant percentage of cases over several years. While such growth is usually benign, there can be rare instances where significant changes, such as foveal extension, might impair visual acuity.
Screening for CHRPE is not only about monitoring the eye but also about serving as an early marker for FAP in cases of atypical lesions. Because atypical CHRPE is associated with genetic mutations in the adenomatous polyposis coli (APC) gene, its identification signals the need for additional systemic evaluations. Early detection of FAP is critical since left untreated, nearly all patients with this syndrome develop colorectal carcinoma by middle age. In families with a known risk, regular retinal examinations provide a non-invasive and quick method of screening for these ocular signs.
For patients, knowing that routine eye exams can serve multiple purposes—both for preserving vision and for catching potential systemic issues—is reassuring. It underscores the comprehensive role that eye care plays in overall health management.
In general, CHRPE does not require any active treatment. The lesions themselves are benign and seldom cause symptoms unless complicated by location or secondary changes. However, periodic follow-up with imaging studies is advisable to track any changes in the lesion’s characteristics.
Although it is uncommon, if a CHRPE lesion extends into the foveal area, visual acuity could be impaired, necessitating more frequent monitoring.
There are rare reports of nodular pigmented adenocarcinomas that arise within areas of CHRPE. While hemorrhagic complications or retinal detachment are unusual, vigilant observation ensures prompt intervention should such changes occur.
In very rare cases, complications such as premacular gliosis or cystoid macular edema can develop when peripheral RPE tumors are present.
For most patients, these possibilities serve as reminders of why regular eye examinations are essential. They help ensure that any unusual behavior in the lesion is caught early, allowing our retina specialists to provide the appropriate personalized guidance and follow-up care.
Contact our experienced retina specialists today to schedule a comprehensive eye examination. Understanding CHRPE and its implications for your health is crucial. Find a top optometrist or ophthalmologist near you in the Specialty Vision directory!
A closer look at atypical CHRPE reveals its unique relationship with genetics, particularly familial adenomatous polyposis (FAP). FAP is caused by mutations in the APC gene, which plays an essential role as a tumor suppressor. Specific mutations, particularly those between codons 446 and 1338, are often found in individuals with the FAP phenotype that includes atypical CHRPE. Conversely, certain mutations (for example, between codons 1445 and 1578) rarely show these retinal changes.
This genetic connection explains why atypical CHRPE is not merely an ocular finding but a significant indicator of a systemic condition. Conditions such as Gardner syndrome (which includes skeletal hamartomas and soft tissue tumors) and Turcot syndrome (associated with various brain tumors) fall under the umbrella of FAP-related disorders. For families with a known history of FAP, the presence of atypical CHRPE should prompt a discussion about genetic counseling and potentially further systemic screening. The eye becomes a window to the rest of the body, and spotting these signs early can lead to life-saving interventions.
The histopathological examination of CHRPE lesions provides deeper insight into the nature of this condition. In solitary and grouped variants, the lesion is characterized by a monocellular layer of enlarged RPE cells. These cells are packed with macromelanosomes, which are large, round deposits of melanin pigment that give the lesions their dark appearance. In areas where the lesion becomes depigmented, a replacement of the RPE and photoreceptor layers by glial cells is often observed.
In some depigmented areas, the membrane underlying the RPE may thicken, which can be detected during detailed imaging studies.
With increasing age, the retinal photoreceptors overlying the CHRPE lesions can show signs of degeneration. This degeneration does not usually affect central vision unless the lesion encroaches upon the macula.
It is significant that both the choroid (the layer supplying blood to the retina) and the inner retinal layers do not show any abnormalities, reinforcing that CHRPE is typically an isolated process.
In contrast, atypical CHRPE lesions associated with FAP display more aggressive changes including hyperplasia (an increase in cell numbers), retinal invasion, and retinal vascular alterations. Such changes are the reason why recognition of the lesion’s pattern is so critical in patients with or without a family history of FAP.
When evaluating pigmented lesions of the retina, a clear and accurate diagnosis is essential. Conditions that may mimic the appearance of CHRPE include choroidal melanoma, choroidal nevus, melanocytoma, or focal pigmentation from inflammatory or toxic causes. Each of these conditions demands a unique approach to management, which is why differential diagnosis is so important.
CHRPE typically has a well-demarcated margin with a sharp boundary between the lesion and normal surrounding tissue. This is in contrast to other pigmented lesions that may have more irregular borders.
Solitary CHRPE lesions are generally larger than 100 micrometers, while atypical lesions seen with FAP tend to be much smaller, around 50–100 micrometers, and often present bilaterally. Other lesions such as choroidal melanoma might have different growth patterns and a less predictable location in the retina.
On imaging modalities like OCT and autofluorescence, CHRPE shows consistent patterns (such as hypoautofluorescence due to melanin) that are typically not seen in conditions like melanocytoma or focal hyperpigmentation.
These distinctions help our retina specialists ensure that no significant condition is overlooked, and they lay the foundation for an appropriate management strategy based solely on the actual pathology present.
Even though CHRPE is generally benign, its propensity for slow growth means that periodic follow-up is advisable. Studies have indicated that in 46–83% of cases, CHRPE lesions enlarge over some years. While their growth is usually not associated with symptoms, a few complications may occur, such as:
If the lesion extends towards the fovea, patients might experience a decrease in central vision, which can affect daily activities like reading and driving.
On occasion, pigmented lesions may evolve into nodular lesions that, if left untreated, have a potential to progress further and even cause serous retinal detachment.
Conditions such as premacular gliosis or cystoid macular edema have been documented, particularly when peripheral RPE tumors arise within CHRPE.
Regular eye examinations are therefore key—not only for monitoring the ocular health associated with CHRPE but also because they provide an opportunity to catch rare complications early. When you visit our office, our retina specialists can review the images from your previous exams and compare them with current findings to track any changes over time.
CHRPE is usually an incidental, benign finding but its various forms and association with FAP in atypical cases warrant routine monitoring. Discuss any findings with our retina specialists to determine if further evaluation is needed, ensuring both your vision and overall health are well cared for.
Contact our experienced retina specialists today to schedule a comprehensive eye examination. Understanding CHRPE and its implications for your health is crucial. Find a top optometrist or ophthalmologist near you in the Specialty Vision directory!
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