Perifoveal Exudative Vascular Anomalous Complex-Like Lesion:A Case Report

Introduction

Exudative maculopathy is seen in various retinal vascular diseases. Retinal vasculopathies cause leakage from capillaries leading to fluid accumulation, exudation, and retinal thickening.¹ In diseases such as macular telangiectasia type 1 (Mac Tel type1) and diabetic macular oedema, there is exudation secondary to structurally or functionally incompetent capillaries at the macula.² Perifoveal exudative vascular anomalous complex (PEVAC) is a newly described entity that is characterized by an idiopathic, perifoveal aneurysm that leads to exudation and retinal thickening. PEVAC and its extended spectrum has been further characterized by multimodal imaging, which has led to a better understanding of the natural course of this lesion.³ We describe a case of a PEVAC-like lesion with arterial loops and its response to treatment with thermal laser.

Case Report

A 75-year-old female presented to our institution complaining of visual decline in the left eye for one year. She had no associated systemic illnesses, and there was no history of ocular treatment. Best-corrected visual acuity was 20/20 in the right eye (OD) and 20/120 in the left eye (OS). Anterior segment was unremarkable in both eyes. Fundus examination in the left eye showed peripapillary staphyloma and multiple peripapillary arterial loops. In the temporal perifoveal area, there was an aneurysmal bulge with surrounding exudation and right-angled arterioles bending into the aneurysmal lesion (Figure 1). 

Fundus fluorescein angiography showed a well-defined hyperfluorescence, owing to the aneurysmal lesion (Figure 2). There was no communication between the aneurysmal lesion and the right-angled arterioles.

showing filling of the perifoveal exudative vascular anomalous complex (PEVAC)-like lesion in early arteriovenous phase. Superotemporal vein filling slowly due to a possible venous obstruction due to arterial loops. (Right) A well-defined hyperfluorescent structure corresponding to PEVAC-like ectasia

Optical coherence tomography (OCT) showed parafoveal cystoid spaces and a hyperreflective structure with back shadowing, corresponding to the lesion (Figure 3).

OCT angiography (OCTA) showed the well-defined aneurysmal lesion with detectable flow in the superficial vascular plexus (SVP) (Figure 4) and no flow in the deep vascular capillary plexus (DVP).

A presumptive diagnosis of PEVAC-like lesion was made based on the characteristic features on multimodal imaging. The PEVAC-like lesion was situated about 1,000 µm temporally from the fovea. Thermal focal laser was done over the lesion using 577 nm wave length (IQ 577; Iridex, Mountain view, CA) with an intensity of 200 mW, 100 ms duration, and 200-µm spot size. At 4-month follow-up, OCT showed reduction in the size of the lesion, disorganization of outer retinal layers, and sparing of the innermost retinal layers. There was also a marginal reduction in the size of the cystoid spaces (Figure 3). OCTA showed the disappearance of the aneurysmal lesion in the SVP (Figure 4), but the BCVA did not show a significant visual improvement.

Discussion

PEVAC was first described in two elderly patients by Querques et al., in 2011.4 In 2017, a multicentric study group described the expanded spectrum of PEVAC with multimodal imaging in 15 eyes.³ PEVAC typically presents as a perifoveal aneurysmal lesion and is associated with small retinal haemorrhages, intraretinal exudation, and sometimes hard exudates. PEVAC lesions are usually situated within 1,500 µm from the center of the fovea. They are also not typically associated with inflammation or other retinal vascular disorders. Even 40% cases were noted to have concomitant age-related macular degeneration and 13% had myopia.³

Similarities with Mac Tel type 1 have been drawn, which also demonstrates perifoveal exudation. However, PEVAC does not show dilated, telangiectatic capillaries like Mac Tel type 1A or 1B lesions. Similarities with retinal angiomatous proliferation (RAP) have also been pondered upon. However, long-term follow-up of PEVAC lesions have not demonstrated any progressive downward growth like in cases of RAP. Anti-vascular endothelial growth factor (VEGF) treatment has been tried in PEVAC with no success.³

Commonly reported associations of arterial loops include branch and central retinal artery occlusions and vitreous haemorrhage; peripapillary macroaneurysms have also been reported in cases with arterial loops.⁵ Degenhart et al., in their series of 21 eyes, demonstrated cilioretinal arteries in 16 eyes and the association with hyphema and amaurosis fugax apart from the previously reported associations with branch retinal artery occlusions and vitreous haemorrhage.⁶ Arterial loops leading to sluggish arterial blood flow, prompting arterio-arterial communications, have been reported.⁷

This case demonstrated a hitherto unknown association of peripapillary arterial loops with a PEVAC-like lesion. We hypothesize that chronic slow flow retinopathy in this case lead to arterio-arterial communications which may then go on to develop into a PEVAC-like ectasia over time. Our case also demonstrated a distinctive rightangled bend of arterioles at the site of the PEVAC-like lesion. Like macroaneurysms, PEVAC-like ectasia may also be a sequela of arterial loops. This hypothesis also lends credence to PEVAC lesions being resistant to anti-VEGF injections as PEVAC is perhaps a response to an anatomical variation and has no relation to VEGF levels.

To the best of our knowledge, an association between arterial loops and PEVAC-like lesion has not been reported. OCT in our case showed a significant reduction in the size of the hyporeflective structure on OCT after thermal laser albeit with disorganized outer retinal layers, suggestive of ablation of the aneurysm. This was also demonstrated by the disappearance of the aneurysm on OCTA post-thermal laser. In this case, thermal laser proved to be a viable treatment option.

Conclusion

PEVAC has to be considered in eyes having aneurysm with exudation without any diabetes, Mac Tels Type 1 or absence of venous occlusion. Angiography is an essential investigation in absence of Angio OCT. Lasers are mainstay of treatment, and intravitreal injection of anti-VEGF are ineffective. Recovery in vision depends on amount of exudation, distance of aneurysm from the fovea and macular oedema.

Financial support

Nil.

Conflict of interest

Nil.