Table 1. Distinguishing features of FAP-associated CHRPE, sporadic solitary CHRPE, and CGP.
Comparative morphologic, imaging, and histopathologic features of FAP-associated CHRPE, sporadic solitary CHRPE, and CGP (bear tracks). Asterisks (*) mark the five features most strongly supported by the evidence as distinguishing FAP-associated CHRPE from sporadic CHRPE and CGP: number, laterality, lacunae, cystoid edema, and PED. FAP-associated imaging data are derived principally from a single multimodal-imaging series [28]; cystoid edema and PED figures are based on small lesion counts and warrant cautious interpretation.
CGP, congenital grouped pigmentation; CHRPE, congenital hypertrophy of the retinal pigment epithelium; FAF, fundus autofluorescence; FAP, familial adenomatous polyposis; OCT, optical coherence tomography; ONL, outer nuclear layer; PED, pigment epithelial detachment.
| Feature | FAP-associated CHRPE | Sporadic solitary CHRPE | Bear tracks (CGP) |
| * Number | Multiple (~10/eye) | Solitary | Multiple (3-30) |
| * Laterality | Bilateral 77-100% | Unilateral | Unilateral, sectorial |
| * Lacunae | Absent | Present 43-78% | Absent |
| * Cystoid edema | Absent | Present 28% | Not reported |
| * PED | Present 22.4% | Not reported | Not reported |
| Size | Small dots | Larger, 4.5 mm | Smaller near disc |
| Shape | Round / pisciform | Round / oval | Falciform, nested |
| Location | Outside posterior pole | Peripheral | Sectorial from disc |
| Halo | Fish-tail ~49% | Pigmented 78% | Not typical |
| OCT outer retina | ONL thinning | ONL thinning | Normal lamination |
| FAF (pigmented) | Hypo 93% | Hypo 100% | Hypo |
| Pigment granule | Macromelanosome | Macromelanosome | Normal ellipsoidal |
| FAP association | 76-80% of FAP | None | None |