Is vasoproliferative tumour (reactive retinal glioangiosis) part of the spectrum of proliferative vitreoretinopathy?

Objectives To investigate the involvement of retinal pigment epithelial (RPE) cells in reactive retinal glioangiosis (RRG; known also as retinal vasoproliferative tumour or massive retinal gliosis). Methods Nine RRG lesions (six in enucleated eyes and three endoresection specimens) were studied employing histological methods. Eight of the nine lesions were also subjected to immunohistochemical evaluation of glial and RPE cell content. Results All lesions consisted of masses within the sensory retina that contained glial cells, abnormal blood vessels, and scattered melanin pigment. Epi- and subretinal membranes were also observed in association with the RRG lesions in all six enucleated eyes (retinal surfaces could not be examined in endoresection specimens). Immunohistochemistry revealed RPE cells in seven of eight RRG lesions and in the associated periretinal membranes. These RPE cells were typically fibroblastic or macrophage-like in phenotype and, within RRG lesions, often perivascular in location. Glia represented the majority of cells in the retinal masses. Conclusions The findings indicate that RPE cells may be involved in RRG. The observations engender speculation that RRG represents a part of the spectrum of proliferative vitreoretinopathy, in which case therapies designed to counter proliferative vitreoretinopathy might also have a role in the management of RRG. Eye (2009) 23, 1851-1858; doi:10.1038/eye.2008.351; published online 14 November 2008