Figure 11-36 Adult-onset foveomacular vitelliform dystrophy. A, Yellowish, egg yolk–like lesion in the central macula. B, Histologic findings include pigment-containing cells in the subretinal space (arrowheads) and outer neurosensory retina (arrow). C, Electron microscopy shows pigment-containing cells filled with lipofuscin (arrowheads). (Courtesy of Sander Dubovy,

MD.)

Dubovy SR, Hairston RJ, Schatz H, et al. Adult-onset foveomacular pigment epithelial dystrophy: clinicopathologic correlation of three cases. Retina. 2000;20(6):638–649.

Diffuse Photoreceptor Dystrophies

Inherited dystrophies affecting the rods and cones are discussed in greater detail elsewhere in the BCSC (see BCSC Section 12, Retina and Vitreous). Only the most common diffuse photoreceptor dystrophy, retinitis pigmentosa, is discussed here.

Retinitis pigmentosa (RP) is a group of inherited retinal diseases characterized by photoreceptor and RPE dysfunction resulting in progressive visual field loss. The genetics of RP are complex. It can be sporadic, autosomal dominant, autosomal recessive, or X-linked. Mutations in the rhodopsin gene (RHO) are the most common cause of autosomal dominant RP. Ophthalmoscopic findings include pigment arranged in a bone spicule–like configuration around the retinal arterioles, arteriolar narrowing, and optic disc atrophy (Fig 11-37A). The disease is characterized primarily by the loss of rod photoreceptor cells by apoptosis. Cones are seldom directly affected by the identified mutations; however, they degenerate secondarily to rods. The term retinitis pigmentosa is a misnomer, because clear evidence of inflammation is lacking. Microscopically, photoreceptor cell loss occurs, as well as RPE hyperplasia with migration into the retina around retinal vessels (Fig 11-37B). The arterioles, though narrowed clinically, show no histologic abnormality initially. Later, thickening and hyalinization of the vessel walls appear. The optic nerve may show diffuse or sectoral atrophy, with gliosis as a late change.