This healthy 19YO male was seen for routine eye examination. Fundus imaging shows bear-track lesions (grouped congenital hypertrophy of the RPE) inferiorly in his right eye. These lesions hypo-autofluoresce.
He had a family history of an aunt with colon cancer. He underwent genetic testing as a child and was fortunately negative for the familial adenomatous polyposis (FAP) gene.
Learning Points:
Group-type congenital pigmented nevi of the RPE (bear tracks) is a relatively rare congenital condition characterized by well-demarcated, flat, hyperpigmented, variably sized RPE lesions that resemble bear tracks. Histopathologically, these lesions are similar to congenital hypertrophy of the RPE (CHRPE), with increased numbers of pigment granules in normal-sized RPE cells. These lesions are benign and cause no visual symptoms.
The major fluorophore in fundus autofluorescence (FAF) is lipofuscin, which is intraliposomal RPE material generated as byproducts of outer segment metabolism. The outer retina overlying these bear track lesions shows varying degrees of atrophy. This leads to less lipofuscin production with hypo-FAF.
Although bear tracks and the typical CHRPE lesions (large, round, unilateral, with depigmented lacunae with age) are not associated with systemic abnormalities, the multifocal, often bilateral, and small comet-shaped lesions with FAP are associated with colonic polyps and cancer (see Romania et al Ophthalmology 1992;99:911-913).
