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Progressive Outer Retinal Necrosis (PORN) A Catchy Acronym But Is the Anatomy Correct? The Salient Observation of Lorenz E. Zimmerman, MD

Curtis E. Margo, MD, MPH1,2; Scott M. Friedman, MD3
[+] Author Affiliations
1Department of Ophthalmology, University of South Florida Morsani College of Medicine, Tampa
2Department of Pathology and Cell Biology, University of South Florida Morsani College of Medicine, Tampa
3Florida Retina Consultants, Lakeland
JAMA Ophthalmol. 2014;132(5):651-652. doi:10.1001/jamaophthalmol.2014.120.
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Progressive outer retinal necrosis (PORN) describes a subset of herpetic viral retinopathy characterized by a rapid clinical course and a distinctive pattern of retinal opacification. The condition is most often caused by varicella-zoster virus. Although easily remembered because of its acronym, the localization of early necrosis in the outer retina has never been confirmed histologically. One of the few pathology reports of PORN before it reaches the stage of full-thickness retinal necrosis actually shows relative preservation of the outer retina in an illustration but fails to comment about this finding.1 We describe the histological findings in an eye with classic PORN that Lorenz E. Zimmerman, MD, once argued the site of initial necrosis was likely the inner retina.

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Figure 1.
Left Macula 1 Day Prior to Enucleation

Nearly confluent yellow lesions appear to involve deep retina. There is virtually no vitreous inflammation. Inset, The macula 1 week earlier. Retinal involvement had progressed rapidly.

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Figure 2.
Histopathological Analysis

A, Retina on the left shows dissolution of its inner layers and loss of photoreceptor outer segments, with relative preservation of the outer nuclear layer and cone photoreceptor inner segments (hematoxylin-eosin; scale bar = 115 μm). B, Higher magnification of the partially necrotic retina with relative preservation of outer layers and capillaries (hematoxylin-eosin; scale bar = 40 μm). C, Large-caliber vessel in the inner retina is suspended within necrotic tissue. Although the outer retina is abnormal, the nuclear layer is identifiable and degenerating photoreceptors can still be recognized (hematoxylin-eosin; scale bar = 40 μm).

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