CHRPE

Introduction

CHRPE is typically associated with genetic defects, and systemically can be associated with familial adenomatous polyposis (FAP).
- Considerably rare, with an approximate prevalence of 1.2%
- Presents in 3 forms, either alone, or in a group known as bear tracks, or following neither.

Dead Giveaways

Histology:

Characterised by grouped pigmentation, present in a monolayer of hypertrophised RPE cells.

Red-Green Fundoscopy Channels:

Whilst this is not a distinct feature of CHRPE, this technique can be used to identify RPE lesions
Red separation (green-free) penetrates deeper into the eye, revealing the choroidal and RPE layers
Green separation (red-free) penetrates not as much into the eye, revealing the RPE and retinal layers
Blue light will view the anterior retinal layers
Hence, if a lesion appears in both red and green separation channels, it must be present in the RPE (overlapping layer).
- Or, it could simply be in multiple layers

Present in both green and red separation channels

diagnostic features

Signs of different CHRPE

Solitary:

Single flat round lesion
Note the single big lesion

Multifocal (Bear Tracks):

A group or cluster of pigmentary lesions
Typically referred to sometimes as Congenital Grouped Lesions of the RPE
Consecutive clusters of pigmentary lesions that looks like animal bear tracks

Atypical

Typically smaller lesions of variable shape, and doesn't follow the previous two presentations