DOMINANTLY INHERITED CYSTOID MACULAR EDEMA - A HISTOPATHOLOGIC STUDY

Background: Dominantly inherited cystoid macular edema was described as a clinically distinct form of macular dystrophy with an onset at approximately age 30 years with slow progression over the ensuing decades. This is the first report of the light and electron microscopic findings in two donor eyes of one of the patients with this clinical entity. Methods: Both eyes were obtained after death and fixed within 24 hours in a buffered 4% formaldehyde-1% glutaraldehyde solution. For light microscopy, tissue was embedded in paraffin and stained with hematoxylin-eosin, periodic acid-Schiff, colloidal iron for mucopolysaccharides, and an antibody to glial fibrillar acidic protein. For ultrastructural investigation, several blocks of choroidal/retinal tissues from the posterior pole, including both maculae, were embedded in epoxy resin and processed for transmission electron microscopy. Results: Major findings included large retinal cysts in the macula, atrophy and marked disorganization of the inner nuclear layer, advanced degeneration of Muller cells with nodular aggregates of basement membrane-like material, and a preretinal membrane. The retinal vasculature did not show excessive endothelial alterations but was surrounded by deposits of multilayered basement membrane in the perivascular space. Conclusion: The authors believe that the pathologic features of dominantly inherited cystoid macular edema are different from those of macular edema caused by other disease processes. The predominant pathologic changes affected mainly the inner nuclear layer. The possibility of a primary disease of the Muller cell is suggested.