Combined Hamartoma of the Retina and Retinal Pigment Epithelium: An Optical Coherence Tomography–Based Reappraisal

Abstract

To analyze the optical coherence tomography (OCT) characteristics of combined hamartoma of the retina and retinal pigment epithelium (CHRRPE) involving the macula. Retrospective, observational case series. setting: Single institutional. Fourteen consecutive patients of CHRRPE were included. The authors analyzed the clinical features, color fundus photography, and swept-source or spectral-domain OCT of all the involved eyes. OCT characteristics, especially the involvement of the retinal pigment epithelium (RPE). A total of 16 eyes of 5 female and 9 male patients were analyzed. The mean age (± SD) was 17.9 ± 6.4 (range 10-34) years. Mean best-corrected visual acuity (± SD) in logMAR was 0.9 ± 0.5 (20/160 ± 20/60). The OCT was suggestive of a focal mass-like lesion primarily involving the inner retinal layers limited externally by the outer plexiform layer (OPL) in 15 eyes (93.7%). The OPL appeared to have a saw-tooth appearance ("intraretinal peaks") in 12 eyes (75%). The convolutions of the OPL were broader and deeper in some eyes (5 eyes, 31.2%), giving an "omega sign" (ω) appearance. The ellipsoid zone appeared intact in 13 eyes (81.2%). The RPE band appeared intact in all eyes. Considering the OCT features, available evidence, and embryology, we propose that the true nature of CHRRPE should be reanalyzed. In our series, CHRRPE was noted to be primarily a hamartoma arising from the inner retinal layers. A majority of cases were limited posteriorly by the OPL without any involvement of the outer retinal layers and RPE.