Spontaneous Resolution of Macular Edema with Abnormal Vessel Crossing near the Central Macula by Congenital Retinal Macrovessel.

We present a case of a congenital retinal macrovessel (CRM) with spontaneous resolution of cystoid macular edema. A 39-year-old woman with sudden decreased vision in her right eye was referred to our clinic and found to have a CRM with macular edema. Her visual acuity was 20/25. A week later, the macular edema disappeared without any treatment, and her visual acuity was 20/15. We performed optical coherence tomography angiography and fluorescein angiography (FA), which revealed no obstruction of retinal flow but a slight disturbance of retinal flow near the central fovea on FA. We encountered a case of spontaneous resolution of macular edema with abnormal vessel crossing near the central macula by a CRM, and multimodal imaging was useful for investigating the pathology of the disease.

Introduction

A congenital retinal macrovessel (CRM) is an abnormal vessel, typically a retinal vein, crossing the central macula above and below the horizontal raphe. This was first reported by Mauthner [1] in 1869. Later in 1982, Brown et al. [2] introduced the term “congenital retinal macrovessels” in a report of 7 cases of abnormal retinal vessels. The prevalence of CRMs is estimated at 1 in 200,000 in the USA [3]. However, this number could be an underestimation, since in most cases of CRMs, the patients have no specific symptoms, and in many cases, CRMs have been diagnosed incidentally during retinal examinations. Here, we present a case of spontaneous resolution of macular edema with abnormal vessel crossing near the central macula by a CRM.

Case Presentation

A 39-year-old Asian woman with sudden decreased vision in her right eye, who had experienced migraines for 20 years, presented to our clinic. The patient's visual acuity was 20/25. The fundus showed abnormal vessel crossing at the central macula (Fig. 1a). Optical coherence tomography (OCT) showed macular edema, but OCT angiography showed no significant changes (Fig. 1b, c). A week later, the visual acuity improved to 20/15, and macular edema was not detected on OCT despite no treatment. Fluorescein angiography (FA) showed a branch from the macrovessel without leakage, blockage, or obstruction of retinal flow (Fig. 2b, c). We performed FA 15 months after her first visit, which showed the same findings as those obtained the first time. The visual acuity remained 20/20 throughout the course, and brain magnetic resonance imaging (MRI) showed no significant changes.

Fig. 1

Color fundus photography (a) and OCT angiography (b) show a large macrovessel extending within the vascular arcade from an inferior nasal vein, crossing the central macula above the horizontal raphe. c Macula edema is detected on OCT. OCT, optical coherence tomography.

Fig. 2

Color fundus photography (a) and FA (b) a week later. FA shows a branch from the macrovessel without leakage, blockage, or obstruction of retinal flow. c OCT a week later shows resolution of cystoid macular edema. FA, fluorescein angiography; OCT, optical coherence tomography.

Discussion

In most cases of CRMs, visual function is not affected, and the condition is incidentally found during routine retinal examinations. However, there are some reports of vision loss caused by macular hemorrhage [4], serous retinal detachment [5], macular edema [6], or branch vein occlusion [7]. In the present case, OCT showed macular edema at the first visit, which disappeared within a week without any treatment. FA showed a macrovessel crossing the retinal artery and another small branch originating from the macrovessel (Fig. 3). There seemed to be a slight disturbance of retinal artery flow compressed by a macrovessel based on FA (online suppl. Video 1; for all online suppl. material, see www.karger.com/doi/10.1159/000524296).

Fig. 3

a FA overlayed on OCT mapping. Macula edema on OCT corresponds to the area where the CRM crosses the fovea. b Macula edema area enlarged on FA. Vein branching from the CRM (blue arrow) and a retinal artery (red arrow) are crossing and compressed by the CRM (*). Both vessels are narrowing after crossing the CRM (arrowhead). FA, fluorescein angiography; OCT, optical coherence tomography; CRM, congenital retinal macrovessel.

We established two hypotheses to explain why the macula edema suddenly occurred and resolved spontaneously. One hypothesis involves the deterioration of the blood-retina barrier of the perifoveal capillary. According to previous reports [6, 7, 8, 9], macular edema with CRMs may be caused by anomalies of the perifoveal capillary bed around the CRMs, which may have affected the blood-retina barrier of the perifoveal capillary for many years. In our case, there was an abnormal vessel crossing near the central macula, which may have caused deterioration of the blood-retina barrier of the perifoveal capillary and incidentally caused macular edema.

Another hypothesis involves the interruption of retinal vessel flow. Sanfilippo and Sarraf [7] identified an abnormally sheathed macrovessel showing macular edema and interruption of retinal vessel flow near the macula on FA, such as branch retinal vein occlusion, and macula edema resolved spontaneously 2 months later. In the present case, we did not detect interruption of any retinal vessel flow on OCTA when the patient was referred to our clinic because real-time FA showed a slight disturbance of retinal flow compressed by the macrovessel even after resolution of macular edema. It is possible that an interruption in the perifoveal vessels caused the macula edema, which resolved spontaneously, as described in a previous report [7].

CRMs are strongly associated with venous abnormalities in the brain. They were first reported by Sanfilippo and Sarraf [7] in 2015. In 2018, Pichi et al. [10] reported that approximately 24% of CRM cases involved systemic vascular abnormalities on brain MRI. In the present case, the patient had a history of migraines but had no signs of abnormalities on brain MRI.

Conclusion

We encountered a case of spontaneous resolution of macular edema with abnormal vessel crossing near the central macula by a CRM, and multimodal imaging was useful for investigating the pathology of the disease.

Statement of Ethics

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. The study has been granted an exemption from requiring ethics approval by Osaka University Ethics Review Board.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

This work was supported by JSPS KAKENHI Grant No. 18 K12142. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Author Contributions

Rina Okamoto, Kentaro Nishida, Taku Wakabayashi, and Kohji Nishida participated in drafting the manuscript. Kentaro Nishida, Chikako Hara, and Hirokazu Sakaguchi participated in the diagnosis and treatment of the patient.

Data Availability Statement

All data generated or analyzed during this study are included in this article and its online supplementary material. Further inquiries can be directed to the corresponding author.

Supplementary data

Click here for additional data file.

Supplemental Video

Click here for additional data file.