Klippel–Trenaunay syndrome presenting with bilateral chronic central serous chorioretinopathy: a case report

Abstract

Background

Klippel–Trenaunay syndrome (KTS) is a rare congenital vascular disorder characterized by capillary malformations, venous and/or lymphatic malformations, and asymmetric limb overgrowth. It results from somatic activating mutations in the PIK3CA gene, leading to dysregulated vascular development. While primarily affecting the skin and musculoskeletal system, ocular manifestations are uncommon. Central serous chorioretinopathy (CSC), a condition involving choroidal vascular hyperpermeability and retinal pigment epithelium dysfunction, has not been previously associated with KTS.

Case presentation

A 52-year-old Iranian male presented with a 6-month history of bilateral vision loss. Ophthalmologic examination revealed best-corrected visual acuity of 20/30 in the right eye and 20/25 in the left eye. Optical coherence tomography (OCT) and fluorescein angiography (FA) confirmed bilateral chronic CSC. The patient exhibited an extensive capillary malformation on the right upper limb and trunk with mild limb hypertrophy. Magnetic resonance angiography (MRA) revealed venous malformations, supporting a diagnosis of previously unrecognized KTS. Laboratory tests excluded secondary causes of CSC. Bilateral photodynamic therapy (PDT) was performed.

Conclusions

This novel case suggests a potential association between KTS-related venous malformations and CSC, possibly mediated by venous overload choroidopathy. Although follow-up was limited, routine ophthalmic screening in KTS patients may be warranted.

Background

Klippel–Trenaunay syndrome (KTS) is a rare congenital disorder characterized by a triad of capillary malformations (e.g., port-wine stains), venous or lymphatic abnormalities, and asymmetric limb hypertrophy [1]. It has an estimated incidence of approximately 1 in 100,000 live births and is caused by postzygotic somatic activating mutations in the PIK3CA gene, resulting in dysregulation of the PI3K/AKT/mTOR signaling pathway and leading to abnormal vascular proliferation and tissue overgrowth. While primarily associated with cutaneous and musculoskeletal manifestations, ocular involvement, including glaucoma and retinal vascular changes, has been documented in a minority of cases [2, 3]. Central serous chorioretinopathy (CSC), a condition involving choroidal vascular hyperpermeability and retinal pigment epithelium dysfunction, has not been previously associated with KTS. We report a novel case of bilateral chronic CSC in a patient with previously undiagnosed KTS, presenting with right upper limb and trunk hemangiomas, suggesting a potential systemic–ocular vascular interplay. This presentation expands the spectrum of ocular manifestations in KTS beyond those previously reported [2, 4].

Case presentation

A 52-year-old Iranian male presented to the retina clinic with a 6-month history of gradually worsening, painless vision loss in both eyes. The patient denied any history of ocular disease, corticosteroid exposure, hypertension, or other significant medical conditions. Family history was negative for similar vascular anomalies, limb hypertrophy, or ocular disorders.

Ophthalmologic examination revealed a best-corrected visual acuity (BCVA) of 20/30 in the right eye and 20/25 in the left eye. Anterior segment examination showed no abnormalities. Posterior segment examination and fundoscopy demonstrated bilateral serous retinal detachment, confirmed by optical coherence tomography (OCT). OCT imaging revealed subretinal fluid and retinal pigment epithelium (RPE) mottling bilaterally, with shaggy photoreceptors indicating chronicity (Fig. 1A, B). Fluorescein angiography (FA) identified multiple punctate areas of leakage without evident choroidal lesions (Fig. 2A, B).

Fig. 1.

Optical coherence tomography image demonstrating bilateral subretinal fluid and shaggy photoreceptors indicative of chronic central serous chorioretinopathy in the right (A) and left eye (B), respectively

Fig. 2.

Fluorescein angiography showing multiple punctate areas of leakage in the right (A) and left eye (B), respectively

During the examination, an extensive erythematous capillary malformation extended from the patient's right upper limb to the ipsilateral trunk (Fig. 3A). Comparative limb measurements confirmed mild right upper limb hypertrophy (Fig. 3B). The patient was unaware of these congenital anomalies. Magnetic resonance angiography (MRA) of the right limb revealed underlying venous malformations, consistent with KTS, as confirmed by dermatologic evaluation based on the clinical triad of capillary malformation, limb hypertrophy, and venous anomalies [1, 5]. No skin biopsy was performed as the diagnosis was clinical and imaging-based. Orthopedic consultation was not required due to mild, non-debilitating hypertrophy.

Fig. 3.

Clinical photograph of erythematous capillary malformation extending from the right upper limb to the ipsilateral trunk (A). Comparative limb measurements confirming mild right upper limb hypertrophy (B)

Laboratory investigations, including serum cortisol levels and autoimmune panels, excluded secondary causes of CSC, such as hypercortisolism or systemic inflammation. No evidence of alternative etiologies, such as posterior uveitis or polypoidal choroidal vasculopathy, was identified.

Due to secondary RPE changes and outer retinal signs of chronicity, such as shaggy photoreceptors, bilateral photodynamic therapy (PDT) with verteporfin was recommended and performed using a standard protocol (6 mg/m², 50 J/cm² for 83 s) targeting areas of leakage on FA. The patient did not return for scheduled follow-up examinations, and, therefore, no further clinical information or outcomes are available at the time of this report.

Conclusions and discussion

This case represents a rare presentation of KTS with bilateral chronic central serous chorioretinopathy (CSC), suggesting that venous malformations inherent to congenital vascular anomalies may exacerbate choroidal congestion via venous overload choroidopathy [6]. Spaide et al. proposed this mechanism as a framework for CSC, wherein impaired venous drainage increases choroidal pressure, leading to RPE dysfunction [6].

The selective involvement of the choroid with normal retinal vasculature on FA can be explained by the distinct venous drainage patterns in the eye. Choroidal veins drain into the vortex veins, which may be affected by the systemic venous malformations in KTS, whereas retinal circulation has a more protected drainage pathway. KTS vascular lesions include persistent embryonic veins, venous ectasias, and microfistulas that can cause chronic venous hypertension [1, 5]. This systemic venous dysregulation plausibly extends to the ocular choroid.

Dermatology consultation confirmed the diagnosis based on the clinical triad; no skin biopsy was performed as it was not clinically indicated. This presentation expands the known ocular manifestations of KTS beyond glaucoma and retinal vascular changes [2] and differs from other CSC associations, such as choroidal hemangioma or hormonal dysregulation [4, 7, 8]. Patients with KTS and extensive vascular malformations may benefit from routine ophthalmic screening to detect vision-threatening conditions, such as CSC.

In conclusion, although our case had limited follow-up, this novel association highlights a potential systemic–ocular vascular interplay in KTS and underscores the importance of multidisciplinary evaluation in such patients.

Abbreviations

KTS

Klippel–Trenaunay syndrome

CSC

Central serous chorioretinopathy

OCT

Optical coherence tomography

FA

Fluorescein angiography

MRA

Magnetic resonance angiography

RPE

Retinal pigment epithelium

BCVA

Best-corrected visual acuity

PDT

Photodynamic therapy

Author contributions

AE: data collection and manuscript drafting. RD: data analysis and manuscript revision. HRE: clinical evaluation and manuscript review. EKP: study design, clinical management, and manuscript editing. All authors read and approved the final manuscript.

Funding

This research received no external funding.

Data availability

Not applicable.

Declarations

Ethics approval and consent to participate

Ethical approval was not required for this single case report, in accordance with the institutional/national policy.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interest

The authors declare no competing interest.