Retinal Physician

JAN-FEB 2017

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26 R E T I N A L P H Y S I C I A N | J A N U A R Y / F E B R U A R Y 2 0 1 7 Dry AMD Masquerade Syndromes PETER BRACHA, MD • THOMAS A. CIULLA, MD, MBA T he prevalence of nonexudative age-related macular degeneration (AMD) will dramatically increase with an aging population. By the year 2020, an esti- mated 196 million people globally will have AMD and 11 million will have significant vision loss. 1 Whenever cases present with atypical features, ophthalmolo- gists should consider other diagnoses, as numerous retinal dis- eases have overlapping features with dry AMD. In this article, we present examples of pattern and cone-rod dystrophies, and maculopathies associated with medication toxicity or systemic disorders, all of which were referred to a retina clinic for assess- ment of dry AMD. ese cases were ultimately diagnosed as other pathologies with the aid of ancillary testing. ey all can be considered "Dry AMD-masquerade syndromes." CASES Cuticular Drusen (Basal Laminar Drusen) A diagnosis of cuticular drusen (Figure 1) was originally considered distinct from AMD, with a more favorable prog- nosis, but more recently it has been considered a subtype of AMD. Despite numerous clinical and histological similarities, important differentiating features exist. On fundus examina- tion, cuticular drusen are small (25-75 microns), yellow-white and nodular. Macular OCT demonstrates these drusen to be blunted, triangular-shaped and below the RPE, giving a saw- tooth pattern. 2 FA strikingly reveals innumerable hyperfluo- rescent drusen that significantly outnumber the drusen noted clinically, yielding the characteristic "stars-in-the-sky" appear- ance during the early arteriovenous phase. 2 Interestingly, on FAF, these drusen are hypoautofluorescent when very small, but also present with a hypoautofluorescent center surrounded by a ring of hyperautofluorescence. 2 Overall, the frequency of choroidal neovascularization seen with this AMD subtype ranges from 4% to 56% depending on the study. 3-5 One-third of patients can develop geographic atrophy. 6 In patients with early-onset, extensive cuticular drusen, a rare complement mutation is associated with an increased risk of developing choroidal neovascularization and type II membranoprolifera- tive glomerulonephritis. 4,7,8 Close ocular and systemic moni- toring is warranted. Peter Bracha, MD, is a resident and omas A. Ciulla, MD, MBA is on the clinical faculty at Indiana University Dept. of Ophthalmology in Indianapo- lis. Neither author reports any financial interests in products mentioned in this article. Dr Ciulla can be reached via e-mail at Figure 1. is 52-year-old female was referred with a 4 month history of progressive blurring of central vision and meta- morphopsia from her le eye (LE). Visual acuity (VA) mea- sured 20/20 both eyes (BE) and fundus examination revealed bilateral macular retinal pigment epithelial (RPE) moling with patches of atrophy in the nasal macula (Figure A). Macular OCT demonstrated areas of outer retinal segment and RPE atrophy and fine sub-RPE drusen BE (Figure B). Fundus autofluores- cence (FAF) vividly demonstrated innumerable, punctate hyperautofluorescent lesions significantly outnumbering the drusen noted clinically, which is characteristic for this disorder. ere were also patches of hypoautofluorescence correlating to RPE atrophy (Figure C). With the aid of multimodal imaging, a diagnosis of cuticular drusen with RPE atrophy was made. In addition to the examples from this case, in another case, a clas- sic appearance is depicted on fluorescein angiography (FA), on which these numerous punctate drusen stain discretely, result- ing in a "stars-in-the-sky" appearance (Figure D) A C B D

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