Presumed Ocular Histoplasmosis Syndrome (POHS) [135,136,137,138] | ||||
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Prevalence | Frequent; present in majority cases | Estimated between 0.3–19% | Uncommon; prevalence not known | Only few cases (< 5) reported |
Location of CNV | CNV is seen at the edge of a pre-existing scar in the macular or peripapillary region | CNV typically grows close to the edge of an atrophic chorioretinal scar | CNV is typically adjacent to the healed choroidal granuloma or to a healed choroiditis scar | CNV is adjacent to chorioretinal scars |
Morphology of CNV | Active lesions have a disciform appearance at the macula, with a green-gray subretinal lacy discoloration and surrounding pigment. Inactive CNV appears as a white disciform scar with fibrovascular tissue | Active CNV appears as an outer retinal lesion close to the scar with associated hemorrhages and intra- or subretinal fluid. | CNV may present as a subretinal lesion with hemorrhages and intra- or subretinal fluid. Rarely, type 1 CNV may be detected only using imaging | CNV presents as a chorioretinal lesion with subretinal fluid and area of retinal hemorrhage |
Associated inflammatory lesions | The triad of POHS includes the presence of peripapillary atrophy or pigmentation, histo spots (focal round-shaped chorioretinal lesions), and absence of overlying vitritis | Recurrent disease appears as an oval or circular whitish focal area of retinochoroiditis in the periphery of old atrophic lesions; dense overlying vitritis (headlight-in-fog); perivasculitis with diffuse venous sheathing; segmental arteriolar plaques | Choroiditis may have amoeboid lesions with central healing and active margins (serpiginous choroiditis) or it may present with choroidal granulomas | There is multifocal chorioretinitis with vitritis; multiple active chorioretinal lesions have the appearance of deep, creamy lesions and are 200–1000 μm in size. Inactive lesions are partly atrophic and partly pigmented with a “target-like appearance.” |