Aneurysmal type 2 neovascularization: A new entity

To report three cases of aneurysmal type 2 neovascularization (AT2), a novel entity within the pachychoroid disease (PD) spectrum.

We conducted an observational retrospective study of three patients with subretinal polyps treated with intravitreal aflibercept. We reviewed clinical and imaging data of the three patients. Best corrected visual acuity (BCVA), central macular thickness (CMT), choroidal subfoveal thickness, choroidal thickness under the polyps and the presence of a dry macula were assessed at baseline and throughout the follow-up.

All of the patients showed granular hypoautofluorescence on fundus autofluorescence. Indocyanine green angiography revealed prominent hyperfluorescent branching vascular networks ending in multiple aneurysmal dilatations. Optical coherence tomography (OCT) demonstrated that the aneurysmal lesions were localized in the subretinal space. Additionally, OCT showed retinal pigment epithelial microtears, the double-layer sign and pachyvessels. En face OCT-A perfectly defined prominent telangiectatic branching vascular networks in all the patients, but only revealed polyps in two out of the three patients. Cross-sectional OCT-A demonstrated polyps as patchy circular hypoflow signals in each case. After the intravitreal treatment, BCVA remained unimproved in all of the patients, despite decreased CMT and achievement of a dry macula, as a result of the development of subretinal fibrosis.

In summary, we describe a new entity within the spectrum of PD, which we have termed AT2. This novel disease is characterized by the presence of aneurysmal dilatations in the subretinal space, along with the typical features of PD, such as choroidal vascular hyperpermeability, thickening of the choroid and pachyvessels.