Choroidal Neovascular Membranes in Retinal and Choroidal Tumors: Origins, Mechanisms, and Effects

Choroidal and macular neovascularization are historically associated with exudative macular degeneration, nonetheless they have been observed in several choroidal and retinal tumors such as nevus, melanoma, osteoma, and hemangioma. This review aimed to elucidate the possible origins of neovascular membranes by examining in vivo and in vitro models compared to real clinical cases. Among the several potential mechanisms examined, particular attention was paid to histologic alterations and molecular cascades. Physical or biochemical resistance to vascular invasion from the choroid offered by Bruch’s membrane, the role of fibroblast growth factor 2 and vascular endothelial growth factor, resident or recruited stem-like/progenitor cells, and others angiogenic promoters were taken into account. Even if the exact mechanisms are still partially obscure, experimental models are progressively enhancing our understanding of neovascularization etiology. Further studies are warranted to establish a decisive connection between choroidal tumors and choroidal neovascular formation.