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Klippel Trenaunay syndrome is cutaneous vascular malformation syndrome involving a triad of capillary and venous malformation and limb hypertrophy. This is a rare syndrome with a wide spectrum of clinical findings that can manifest during infancy and can progress throughout childhood and adulthood. This activity reviews the clinical manifestations, diagnostic workup, differential diagnosis, and management of Klippel Trenaunay syndrome and highlights the role of the interprofessional team in facilitating improved care and preventing complications seen in this condition. Objectives: Outline the etiology of Klippel Trenaunay syndrome. Describe the clinical features of Klippel Trenaunay syndrome. Review the management options available for Klippel Trenaunay syndrome. Explain the role of the interprofessional team in facilitating improved care and preventing complications seen in patients suffering from Klippel Trenaunay syndrome. Access free multiple choice questions on this topic.

Klippel–Trenaunay syndrome (KTS), historically referred to as Klippel–Trenaunay–Weber syndrome, is a vascular malformation syndrome characterized by variable involvement of cutaneous capillaries, veins, and lymphatics, with hypertrophy of soft tissues and bones of the affected limb. The term “Weber” has largely been abandoned in modern usage to avoid confusion with Parkes Weber syndrome, a distinct high-flow vascular disorder characterized by arteriovenous malformations. This syndrome is also referred to as capillary-lymphatic-venous malformation (CLVM), reflecting the changes seen in those vessels. This condition was first described in 1900 by 2 French physicians, Maurice Klippel and Paul Trenaunay. KTS is a clinical diagnosis made by the presence of at least 2 of the 3 classic findings: localized cutaneous capillary malformations, venous abnormalities, and limb hypertrophy. The presence of arteriovenous malformations is now considered a separate entity, termed Parkes Weber syndrome, and is distinct from KTS.[1][2]

Recent studies have linked the etiology of KTS to somatic mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit (PIK3CA) gene. This leads to activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) and cell overgrowth through dysregulation of the mTORC2 pathway.[3][4] Mutations occur in the embryological stage of development involving angiogenesis, reflecting findings seen in this condition. Now, KTS is grouped under the umbrella of similar overgrowth syndromes - PIK3CA-related overgrowth spectrum (PROS). Several overgrowth syndromes with overlapping clinical manifestations have been identified, each involving multiple mutations in the PIK3CA gene. In rare instances, translocations of chromosomes 5-11 and 8-14 have been reported.[2]

KTS primarily involves the capillary, venous, and lymphatic systems, with varying degrees of hypertrophy of tissue and bone. This condition predominantly affects the lower limbs and affects both sides equally. In rare cases, upper extremity, head and neck area, and bilateral involvement may be seen.[6] Capillary manifestations are flat, red, or purple capillary port-wine stains and are seen in 90 to 100% of cases. This is usually the first clinical finding present at birth and enlarges as the child grows.[5] Venous malformations are seen in 70 to 100% of patients and consist of varicosities in the superficial and deep venous systems, persistent embryonic veins, and aplasia/hypoplasia with valvular incompetence. The embryonic veins, which usually regress prior to birth, are persistent and are functionally incompetent, leading to venous stasis and chronic thrombosis. Venous malformations can occur in the gastrointestinal tract, especially in the colon, and can present with gastrointestinal bleeds. On exam, dilated, tortuous veins are seen in the affected limb, with swelling and discoloration. Patients can also present with recurrent deep vein thrombosis, leading to pulmonary embolism.[5][7][8] Lymphatic malformations are seen in 15% to 50% of cases and include lymphedema and cystic lymphatic collections.[9] Musculoskeletal findings include soft tissue and bone hypertrophy in an extremity, leading to a limb-length discrepancy. Rare physical findings include syndactyly, polydactyly, and clinodactyly. Other uncommon symptoms include seizures, developmental delay, and genitourinary abnormalities presenting as hematuria.[9][10]

KTS is a clinical diagnosis characterized by the presence of 2 of the 3 classic features. Imaging is recommended to evaluate underlying venous/lymphatic malformations and soft-tissue/bone hypertrophy, and to map the extent of disease and complications. A color Doppler ultrasound can be an initial step to assess varicosities, venous malformations, or the presence of thrombus. However, magnetic resonance imaging and magnetic resonance venography can be more useful for assessing the extent of underlying malformations.[5][10] Elevated D-dimer is seen in most patients.[7]

A multi-disciplinary team approach with care coordination is optimal in patients with KTS. The mainstay is symptomatic care with medical management, with only a few cases needing surgical intervention. Skincare is important to prevent superficial infections and bleeding secondary to scratching. Children are monitored closely for limb length discrepancy and referred to orthopedics for orthotics or surgical corrections as needed. Compression stockings, limb elevation, and intermittent pneumatic compression devices are used to minimize lymphedema and venous insufficiency. Sclerotherapy, both conventional and micro-foam, has been used for capillary, venous, and lymphatic malformation with promising results. Laser treatment can be offered for port-wine stains.[6] Surgical management is reserved only for cases refractory to medical therapy and consists of endovascular ligation of embryonic veins and stripping of severe varicose veins.[7] Estrogen-containing contraceptives should be avoided due to the risk of thrombosis. Pregnant patients need anti-thrombotic therapy as prophylaxis due to a high risk of deep venous thrombosis and pulmonary embolism.[4] Bleeding due to coagulopathy should be recognized promptly and treated with supportive care, fresh frozen plasma, and low molecular weight heparin. Patients undergoing surgical procedures should receive low-molecular-weight heparin prior to the procedure to reduce the risk of intravascular coagulation. Rapamycin is a relatively newer therapy that can halt the progression of vascular malformation and improve the quality of life in patients with KTS. This drug works by inhibiting the PI3K/AKT/mTOR pathway. Rapamycin-protein complex inhibits the action of mTOR1, leading to the arrest of cell growth, thereby preventing tissue overgrowth. Patients on this medication need to be monitored closely for adverse effects and toxicity, such as hematological and lipid abnormalities.[9]

KTS should be differentiated by the other overgrowth syndromes presenting as hemihypertrophy and other vascular syndromes with cutaneous lesions such as CLOVES (congenital lipomatous overgrowth vascular malformation with epidermal nevus and skeletal abnormalities); MCAP syndrome (megalencephaly-capillary malformation); DCMO (diffuse capillary malformation with overgrowth); FAO (fibro adipose overgrowth); proteus syndrome-post-natal skeletal and connective tissue overgrowth with epidermal nevi and vascular malformation; Beckwith-Wiedemann syndrome characterized by hemihypertrophy, neonatal hypoglycemia, omphalocele, ear abnormalities; Maffucci syndrome-multiple enchondromas; plexiform neurofibromatosis in NF-1 presenting as localized hypertrophy.[11] A special distinction should be made with respect to Parkes-Weber syndrome (PWS), as KTS and PWS can be easily confused and often mistaken for each other. PWS is characterized by soft-tissue and bone hypertrophy with high-flow arteriovenous malformations and fistulas.[1]

KTS presents with a wide spectrum of clinical findings, and prognosis is related to the severity of vascular malformations. The malformations progress over time with ongoing overgrowth and worsening venous insufficiency. Acute bleeding from gastrointestinal malformation can lead to exsanguinating blood loss with a mortality risk if not promptly treated. Recurrent deep venous thrombosis leads to the risk of pulmonary embolism, which can be massive and fatal.[2]

Cellulitis of an affected extremity due to stasis and the lymphatic leak can lead to sepsis from neglected skincare. Severe stasis from venous and lymphatic abnormalities leads to an increased risk of localized coagulopathy with elevated D-dimer levels in patients with KTS. Bleeding from gastrointestinal tract vascular malformations can be chronic and occult, requiring multiple transfusions and iron supplementation, or bleeding may be life-threatening with associated disseminated intravascular coagulopathy. Recurrent pulmonary embolism secondary to deep venous thrombosis can cause chronic changes in the small vessels, resulting in pulmonary hypertension. Limb hypertrophy may require debulking surgeries to improve mobility and ambulation.[9][10]

Patients with KTS need to be aware of the progressive nature of this condition. In children who are diagnosed with KTS, parents need to be educated on possible complications and to ensure close follow-up to monitor for limb length discrepancy and timely management. Patients should be educated on proper skin care to prevent complications arising from superficial infection. Patients scheduled for elective surgery should be aware that anti-thrombotic prophylaxis is required 2 weeks prior to surgery. Pregnant women need to be closely monitored for a higher risk of thrombosis. Education should be provided to seek immediate medical attention for acute gastrointestinal bleeding.

KTS is a complex vascular malformation syndrome with multi-system involvement. A collaborative approach among health care professionals is important to provide optimal care for these patients. The diagnosis is usually considered by the pediatric provider, as clinical findings are often seen in the neonatal period and throughout childhood. Referral to a dermatologist for confirmation of the diagnosis and to radiologists for consultation can aid in the appropriate evaluation of these patients. Patients with limb length discrepancy may benefit from orthopedic expertise for orthotics or epiphysiodesis, and in cases of severe hypertrophy, de-bulking procedures. Hematologists are often involved due to the high risk of thrombosis and the need for prophylaxis during surgeries. Vascular surgery involvement may be required for chronic venous insufficiency for sclerotherapy and, in refractory cases, open surgical procedures. Larger institutions have specialized clinics for patients with KTS that consist of a multidisciplinary team, including dermatologists, orthopedists, and vascular surgeons. Medical and surgical care should be tailored to each patient based on the extent of disease involvement. The primary care provider plays an important role in coordinating care among various specialists to optimize outcomes.