| Introduction: Klippel–Trenaunay syndrome (KTS) is a rare vascular anomaly within the PIK3CA-related overgrowth spectrum (PROS), classically presenting with the triad of capillary malformations, venous abnormalities, and soft tissue or bony hypertrophy. Although lower limb involvement is most common, upper limb presentation is uncommon and can pose diagnostic and therapeutic challenges. Case: A 15-year-old female presented with progressive hypertrophy of the left upper limb since birth, associated with a port-wine stain extending to the axilla. Examination revealed limb enlargement in both length and girth, prominent superficial veins and varicosities, and multiple papular lesions with intermittent serous discharge in the axilla. The skin was thickened, warm, and showed hyperpigmentation and crusting, though no bruit, pulsation, ulceration, or active infection was detected. Based on the coexistence of capillary malformation, venous anomalies, and soft tissue hypertrophy, a clinical diagnosis of KTS was established. Diagnosis is largely clinical but can be supported by imaging to assess the extent of malformations. Management is multidisciplinary, involving dermatology, interventional radiology, and vascular surgery. Symptomatic strategies include compression therapy, sclerotherapy, and laser ablation. Sirolimus has recently shown promise, particularly in cases with lymphatic involvement. Conclusion: This case highlights an unusual upper limb presentation of KTS and emphasizes the importance of recognizing atypical disease patterns. Individualized, multidisciplinary management is essential for optimal outcomes in patients with PROS disorders. |
