Neovascular Phenotypes: Retinal Angiomatous Proliferation (RAP) or Type 3 Neovascularization Authors:

Over 100 years ago, Oeller described for the first time the presence of anastomoses between the retinal and choroidal circulations in eyes with disciform scars(1). Later, these were recognized in association with laser photocoagulation(2), radiotherapy(3), chorioretinal inflammatory diseases(4) and parafoveal telangiectasias(5). The interest in this condition even led to anatomopathological studies in disciform scars from late agerelated macular degeneration (AMD)(6). In 1992, Hartnett et al.(7) described nine cases of retinal neovascularization, to which they referred as “deep retinal vascular anomalous complex”. In 2000, Slakter et al.(8) described chorioretinal anastomosis in eyes with pigment epithelial detachment (PED) and indocyanine green angiography (ICG-A) hot spots but it was Yannuzzi et al.(9) who coined the term retinal angiomatous proliferation (RAP) when in 2001 the authors described chorioretinal anastomoses as a neovascular proliferation originating deeply in the retina. In 2001, Yannuzzi et al. described chorioretinal anastomosis as neovascular proliferation with origin in the retina, and proposed the designation of RAP – retinal angiomatous proliferation(9). Still, several authors(10-13) maintained the designation of chorioretinal anastomosis, proposing a choroidal origin for this clinical entity. In 2008, Yannuzzi et al.(14) escribed 5 cases of RAP with the neovascular complex originating in the choroid instead of the retina, and proposed that RAP should be called type 3 neovascularization instead. The two terms have been used interchangeably ever since(15). However, RAP is still the most common designation.