Congenital Hypertrophy of the Retinal Pigment Epithelium (CHRPE) is a benign eye condition. It refers to a specific type of lesion found in the retina, specifically within the retinal pigment epithelium. The term “with lacunae” describes distinct, clear areas present within these lesions. CHRPE with lacunae is often discovered incidentally during routine eye examinations.
Understanding CHRPE with Lacunae
CHRPE lesions typically appear as dark, flat, and well-demarcated areas on the retina. Their color can range from light gray to brown or black, often with smooth or scalloped margins. These depigmented zones may gradually progress over time, potentially involving the entire lesion.
These clear areas give the lesion a characteristic “bear track” or “footprint” appearance, especially when multiple lesions are grouped together. CHRPE lesions vary in size, from approximately 100 micrometers to several disc diameters. They are generally located in the peripheral retina, though they can occasionally be found in the peripapillary region, near the optic nerve, although they may enlarge over time, making them easier to detect later in life.
Clinical Significance and Associations
Isolated CHRPE with lacunae typically does not affect vision or lead to serious eye problems. Patients with solitary CHRPE usually do not experience symptoms, and the prognosis is excellent. These lesions are not associated with an increased risk of systemic disease.
A significant association exists between multiple or bilateral CHRPE lesions, particularly those with lacunae, and Familial Adenomatous Polyposis (FAP). FAP is a genetic condition caused by a mutation in the APC gene, which significantly increases the risk of developing colon cancer, with nearly all untreated FAP patients developing colorectal carcinoma by middle age. While a single CHRPE lesion is generally not a concern for FAP, the presence of multiple, bilateral lesions, especially those with irregular borders or a “fish-tail” shape, can be a strong indicator. These FAP-associated CHRPE lesions are often smaller, typically 50-100 micrometers in diameter. Their presence can precede the development of intestinal polyps, making them a valuable early screening marker for FAP in at-risk individuals.
It is important to understand that CHRPE itself is not cancerous and does not transform into cancer. However, if multiple or bilateral lesions are present, genetic counseling and screening for FAP are warranted. This often involves a multidisciplinary approach with gastroenterologists for colorectal cancer screening.
Diagnosis and Follow-up
CHRPE with lacunae is primarily diagnosed through a comprehensive dilated eye examination performed by an ophthalmologist. While not always necessary for diagnosis, specific imaging techniques can be used to document the lesions.
Fundus photography is useful for documenting the lesions and monitoring for any changes over time. Optical coherence tomography (OCT) can reveal hyperreflectivity and thickening of the retinal pigment epithelium, with an absence of RPE and increased light transmission in areas of lacunae. Follow-up protocol for isolated CHRPE usually involves routine eye exams to monitor for rare changes such as slight enlargement or alterations in pigmentation. If multiple or bilateral lesions are present, discussing concerns about FAP risk with an eye care professional is important. They may recommend genetic testing or referral to a gastroenterologist for colorectal cancer screening.