Is vitreoretinal traction the cause of ‘Combined Hamartoma of the Retina and Retinal Pigment Epithelium’ (CHRRPE)? A case series and proposal for ‘Traction-Induced Retinal and Retinal Pigment Epithelium Lesion’ (TRIPEL)

PURPOSE: Combined hamartoma of the retina and retinal pigment epithelium (CHRRPE) is traditionally described as arising from hamartomatous proliferation. We hypothesize that posterior hyaloid membrane (PHM) traction is the primary driver with secondary retinal/RPE changes, supported by imaging and surgical outcomes. METHODS: Dual-center retrospective series of 64 eyes with 'CHRRPE' and OCT imaging. RESULTS: Mean age was 16.2±16.9 years. The PHM was adherent and thickened on OCT in 97%, with broad (>1500µm) attachment in 76%. Traction was present in all eyes (mini-peaks 69%, maxi-peaks in 73%).Thirty-six eyes had follow-up (mean 6.3±5.7 years). Those undergoing surgery (n=15) were younger (6.6 vs 15.0 years, p=0.010), more likely to have macular phenotype (80% vs 50%, p=0.008), and had worse baseline visual acuity (1.01±0.62logMAR [20/200] vs 0.52±0.38logMAR [20/66], p=0.024) versus observation.Surgery resulted in greater reduction in CST (-183±168µm vs -47.4±179µm, p=0.007), reduction in clinically apparent pigmentary change (100% vs 15%, p<0.001), and visual acuity improvement (-0.26±0.46logMAR [13 letter gain] vs +0.29±0.67logMAR [15 letter loss], p=0.045) versus observation, including after adjustment for follow-up. Traction features resolved postoperatively in all cases. CONCLUSION: Traction appears to be a defining feature of CHRRPE. We propose the term 'Traction-Induced Retinal and Retinal Pigment Epithelium Lesion' (TRIPEL) to reflect the pathophysiology.