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At a glance

It is a rare congenital medical condition characterized by the association of soft tissue and bony hypertrophy, venous malformations, lymphatic abnormalities, and cutaneous capillary malformations. The main characteristics that confirm the diagnosis are port-wine stains (pathognomonic), venous and lymphatic malformations, and soft-tissue hypertrophy of the affected limb. Patients affected with large arteriovenous malformations may be at risk of peripheral thrombosis causing potentially a pulmonary embolism.


Angio-Osteohypertrophy Syndrome; Hemangiectatic Hypertrophy Syndrome; Osteohypertrophic Varicose Nevus Syndrome.

N.B.: Formerly called the Klippel-Trénaunay-Weber Syndrome, but no longer accurate (see History).


First described in 1900 by two French physicians, Maurice Klippel and Paul Trénaunay, under the name of “naevus varicosus osteohypertrophicus” (“Naevus variqueux osteohypertrophique”). When Klippel and Trénaunay described this condition, the English dermatologist Parkes Weber (see Other conditions to be considered) reported a combination of “hemangiomas” and overgrowth of limbs. For many years, the last names of all three physicians combined together to term the “Klippel-Trénaunay-Weber Syndrome,” which continues to be wrongly used to this day. Genetic evidences have confirmed Parkes Weber and Klippel-Trénaunay Syndromes are entirely different.


Unknown, but very rare. No racial predilection. Males and females equally affected. The disorder occurs worldwide.

Genetic inheritance

Causes unknown, may be multifactorial, but usually assumed to be a sporadic disorder. Although there is no evidence that it is genetically transmitted; however, there is some evidence that it may be the result of a translocation at t(8;14)(q22.3;q13) or an association with the VG5Q gene that encodes a potent angiogenic factor.


The cause of the soft tissue and bony hypertrophy has not been elucidated, but is postulated to result from the increased blood supply and local growth factors. The disorder may be caused by a genetic mutation or by mesodermal abnormalities during fetal development, intrauterine damage to the sympathetic ganglia (or intermediolateral tract) leading to dilated microscopic arteriovenous anastomoses.


A port-wine stain and venous varicosities in association with bony and soft tissue hypertrophy, radiology (elongation and cortical thickening of affected bones), and arterial and venous evaluation (angiography, venography) are characteristics. Histology shows capillary spread of the papilla dermis adjacent to the lesion, but also in deeper layers of dermis and subcutis.

Clinical aspects

The cutaneous stains are the earliest signs, with lateral plain hemangiomas (85% of cases), often affecting the lower limbs (95% of cases). Osteohypertrophy, usually affecting the involved bone, is often not present at birth, but appears within the first few months of life. Associated anomalies include ocular anomalies, glaucoma, cerebral aneurysm, spinal cord arteriovenous malformations, gastrointestinal hemorrhage, and severe menorrhagia. Eighty percent of the cord lesions may bleed ...

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