Definition
A sporadic overgrowth disorder with capillary malformation, venous malformation with or without lymphatic malformation, and soft tissue or bony hypertrophy of a limb.
Aetiology
- Somatic mosaic PIK3CA mutations, within the PIK3CA related overgrowth spectrum
- Not inherited
Clinical Features
- Port wine stain, present at birth
- Persistent lateral marginal vein of Servelle
- Lower limb involved far more often than upper limb
- Leg length discrepancy in 84% of those referred to orthopaedics
- Macrodactyly, foot enlargement and syndactyly
- Pain, venous thrombosis and bleeding from malformations
- Scoliosis and angular deformity in some
Investigations
- Long leg radiographs or scanogram for discrepancy, see leg length discrepancy
- MRI defines the extent of vascular and soft tissue involvement
- Duplex ultrasound confirms deep venous patency before surgery
Differential Diagnosis
- Parkes Weber syndrome, with high flow arteriovenous fistulae
- Proteus syndrome
- Neurofibromatosis
- Isolated hemihypertrophy
- Maffucci syndrome
Management
- Compression garments. First line for venous symptoms
- Shoe raise. Minor discrepancy
- Epiphysiodesis. Timed to correct the predicted discrepancy at maturity
- Debulking or ray amputation. Foot overgrowth that prevents shoe wear
- Sclerotherapy. Symptomatic venous or lymphatic malformations
- Sirolimus. Targets the PIK3CA pathway in complex disease
Complications
- Deep vein thrombosis and pulmonary embolism, highest after surgery
- Consumptive coagulopathy and bleeding
- Pathological fracture
References
- Jacob AG, Driscoll DJ, Shaughnessy WJ, Stanson AW, Clay RP, Gloviczki P. Klippel-Trénaunay syndrome. Spectrum and management. Mayo Clin Proc. 1998, 73(1), 28-36. PubMed
- Schoch JJ, Nguyen H, Schoch BS, Anderson KR, Stans AA, Driscoll D, Tollefson M. Orthopaedic diagnoses in patients with Klippel-Trenaunay syndrome. J Child Orthop. 2019, 13(5), 457-462. PubMed
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 19 October 2026.