Multimodal Imaging Studies of Pigmented Paravenous Retinochoroidal Atrophy: A Case Report

Introduction

Pigmented paravenous retinochoroidal atrophy (PPRCA) is rare, and limited epidemiological data are available regarding its precise prevalence. Despite hypotheses regarding the contributions of inflammatory, developmental, and genetic factors, the etiology of PPRCA remains unclear [1]. Current evidence implicates a dominant missense variant in retinitis pigmentosa GTPase regulator-interacting protein 1 (RPGRIP1) [2] and pathogenic mutations in cone-rod homeobox (CRX) [3]; however, genotype–phenotype correlations have not yet been systematically evaluated. Clinical manifestations of PPRCA typically comprise retinochoroidal atrophy and affect the retinal pigment epithelium (RPE) and choriocapillaris; pigmentation occurs along the retinal veins, often in a bilateral symmetric pattern [4].

During the diagnosis of the PPRCA case described in this report, multimodal imaging played a critical role. Ultra-widefield (UWF) imaging (200Tx, Optos, UK) provided a panoramic retinal assessment; fundus fluorescein angiography (FFA, 200Tx, Optos) revealed the status of the retinal and choroidal circulation; optical coherence tomography angiography (OCTA, RTVueXR, Optovue, USA) noninvasively delineated the vasculature at various hierarchical levels; spectral-domain optical coherence tomography (SD-OCT, Spectralis, Heidelberg, Germany) displayed the retinal cross-sectional morphology; and multifocal electroretinography (mfERG, RETIport/scan 21, Roland Consult, Germany) objectively quantified localized retinal function. Integration of these findings elucidated the structural and functional alterations characteristic of PPRCA.

The combination of these imaging modalities allows comprehensive evaluation of structural and functional changes in PPRCA, supporting accurate diagnosis and improved understanding of disease pathogenesis. There is currently no established treatment to reverse or cure PPRCA. Management primarily consists of regular monitoring for disease progression, and the role of potential therapeutic approaches requires further investigation. Here, we present a detailed multimodal imaging analysis of PPRCA in a 56-year-old woman, including UWF imaging, FFA, OCTA, SD-OCT, and mfERG; we discuss how these findings may refine understanding of PPRCA pathogenesis.

Case Report

A 56-year-old woman reported vision deterioration in the left eye for 3 days, without any history of systemic illness or congenital disease. Best-corrected visual acuity was 20/50 in the right eye and 20/200 in the left eye. No abnormalities were observed in the anterior segment of either eye, and intraocular pressure was normal bilaterally.

UWF fundus imaging showed retinochoroidal atrophy and pigment clumps originating at the optic disc and extending along the retinal veins in both eyes; macular involvement was evident in the left eye (Figure 1). FFA demonstrated transmitted hyperfluorescence in both eyes, consistent with RPE degeneration, as well as more extensive choriocapillaris atrophy and blocked fluorescence in areas of pigment accumulation (Figure 1).

Wide-field FAF revealed sharply demarcated hypoautofluorescent patches corresponding to RPE disruption and diffuse hyperautofluorescence at the margins of trophic lesions in both eyes (Figure 2). mfERG indicated decreased amplitude across all waveforms and substantially reduced response density in the right eye (Figure 2).

OCTA showed a normal macular superficial capillary plexus, a greatly rarefied macular deep capillary plexus, and a macular choriocapillaris containing several flow voids in both eyes (Figure 3). Quantitative vascular density and retinal thickness measurements indicated slightly reduced retinal blood flow density and decreased inner retinal layer thickness in both eyes (Figure 4). SD-OCT demonstrated absence of the myoid, ellipsoid, and interdigitation zones in the macular region, with partial preservation of the RPE (Figure 3).

Based on the characteristic fundus findings and multimodal imaging results, a diagnosis of bilateral PPRCA was made. At the 6-month follow-up assessment, best-corrected visual acuity remained 20/50 in the right eye and 20/200 in the left eye; dilated funduscopic examination showed no clinically significant lesion progression.

Discussion

This case report illustrates the characteristic multimodal imaging features of PPRCA and underscores the value of advanced imaging, particularly OCTA, in clarifying the underlying choroidal vascular pathology. The principal finding is that a comprehensive multimodal approach is essential to confirm the diagnosis of PPRCA and delineating the full extent of structural and functional impairment, which predominantly indicates choriocapillaris compromise.

The patient exhibited no signs of ocular inflammation, including anterior chamber inflammatory activity, and had no history of systemic disease. These findings did not support ocular involvement secondary to inflammatory or systemic conditions. Based on the funduscopic appearance and ancillary examinations, the diagnosis of PPRCA was definitive.

To our knowledge, few case reports concerning OCTA features of PPRCA have been published [4,5]. Consistent with previous findings, our patient showed characteristic FAF patterns of hypoautofluorescence and SD-OCT evidence of outer retinal layer disruption. However, the present case offers deeper insight into vascular alterations through OCTA assessment. Whereas earlier reports noted choriocapillaris flow voids and deep capillary plexus rarefaction, our quantitative OCTA analysis objectively demonstrated reduced vascular density and thinning of the inner retinal layers. Bianco et al [2] reported rarefaction of the deep capillary plexus, relative sparing of the superficial capillary plexus, and loss of the choriocapillaris in a patient with PPRCA. Parodi et al [6] described specific impairment at the level of the deep capillary plexus, which could result in thinning of the ganglion cell complex and outer nuclear layer, with variable choroidal involvement. In the present case, OCTA enabled stratified and quantitative analysis of the retinal and choroidal vasculature. It revealed choriocapillaris flow voids, reduced vascular density, and thinning of the inner retinal layers, thus identifying subtle alterations in the retina and choroid attributable to PPRCA. The concordance of these structural and quantitative findings across reported cases strengthens the hypothesis that PPRCA involves primary impairment of the choroidal vasculature, particularly the choriocapillaris, with secondary effects on the deep retinal capillary plexus and outer retinal layers.

In terms of clinical presentation and course, our patient shared several features typical of PPRCA: she remained asymptomatic until recent visual deterioration, had no clinically significant family history or systemic disease, and displayed a bilateral condition. However, severity differed between the 2 eyes, with greater involvement in the left eye. Management in this case consisted of observation and regular follow-up, consistent with the standard approach for PPRCA, given that no established treatment can reverse or cure the condition. The stable clinical findings at the 6-month follow-up align with the typically slow or nonprogressive course reported in many cases.

PPRCA leads to RPE atrophy, which reduces local vascular endothelial growth factor (VEGF) levels. Given the essential role of VEGF in maintaining choriocapillaris homeostasis [7], this deficiency provides a plausible explanation for the choriocapillaris impairment observed in the disease and supports further investigation into angiogenic factors. Notably, the VEGF family exhibits functional heterogeneity that extends beyond vascular maintenance. A recent study demonstrated that, unlike VEGF-A, VEGF-B does not promote pathological angiogenesis but acts as a potent photoreceptor protector in degenerative models through activation of the VEGFR1/AKT pathway [8]. Because photoreceptor loss is a key pathological outcome in PPRCA, investigation of VEGF-B’s neuroprotective properties represents a promising therapeutic direction.

Further exploration of pathogenic genes associated with PPRCA is also warranted. To date, a dominant variant in RPGRIP1 [2] and mutations in CRX [3] have been linked to PPRCA. However, the absence of these variants has been reported in several cases [9]; recent studies describe simultaneous PPRCA and retinitis pigmentosa in the contralateral eye [9,10]. These observations suggest that PPRCA pathogenesis is heterogeneous and may involve multiple molecular mechanisms, underscoring the need for comprehensive future investigations.

Limitations of this report include its single-case focus, short follow-up period, and constrained imaging resolution. Future studies with larger sample sizes and longer follow-up durations are needed to further elucidate the pathogenesis of PPRCA.

Conclusions

This report reinforces the essential role of multimodal imaging in diagnosing and characterizing PPRCA. The integration of UWF, FFA, FAF, SD-OCT, and mfERG provided comprehensive assessment, whereas OCTA offered valuable insights into choroidal and deep retinal capillary pathology, suggesting that the disease primarily affects the choriocapillaris. Future research should prioritize larger longitudinal studies and genetic investigations to further clarify the pathogenesis and potential therapeutic targets, including VEGF, for this rare condition.