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

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. 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. 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.