The persistent embryonic vein in Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a congenital malformation syndrome with prominent vascular anomalies. A persistent embryonic vein (PEV) may be located on the affected leg(s) of patients with KTS. Our understanding of PEVs of the legs is limited and their nomenclature is confusing. The objective of this study was to obtain further insight in the prevalence, nomenclature and etiology of PEVs of the legs in KTS and to propose a standardized description of anomalous leg veins in KTS. We investigated 70 KTS patients for the presence of PEVs (lateral marginal vein, LMV) of the legs by duplex ultrasonography. We performed histopathological analysis of a surgically excised PEV (LMV) of a typical KTS patient, and we conducted an extensive literature study. Duplex ultrasonography showed LMVs in 12/70 (17.1%) patients. The terms used to describe PEVs in the leg are quite variable, while indicating only two types: lateral marginal vein (LMV) and persistent sciatic vein (PSV). The histology of the excised LMV showed remarkable similarity with that of varicose veins found in the general population. In conclusion, the prevalence of LMVs in our KTS cohort is 17.1%. Two PEVs can be found in the legs and we propose nomenclature based on anatomical criteria, thereby using only the terms persistent lateral marginal vein and persistent sciatic vein, combined with the patency of the deep venous system. We hypothesize that PEVs are most likely caused by a genetic defect leading to abnormal venous pattern formation, which is further supported by our histopathological findings.

Sonographic identification of lower limb venous hypoplasia in the prenatal diagnosis of Klippel-Trénaunay syndrome.

We report the prenatal identification of lower-limb venous hypoplasia to support a provisional prenatal diagnosis of Klippel-Trénaunay syndrome (KTS). Ultrasound assessment of a fetus with marked lower-limb edema, cystic areas in the abdomen/pelvis/lower limbs and abnormal development of the feet demonstrated bilateral hypoplasia of the femoral and popliteal veins. The external iliac veins and the great saphenous veins were seen to be normal. The lower limb arterial system was present. These findings supported KTS as the most likely provisional diagnosis, and postnatal clinical evaluation confirmed that the infant is best classified in the spectrum of KTS. Venous hypoplasia was confirmed with a postnatal ultrasound examination of the lower limbs. This case suggests that careful examination of the lower-limb venous system may be helpful in making the prenatal diagnosis of KTS.

Application of the surface rendering technique of three-dimensional ultrasound in prenatal diagnosis and counselling of Klippel-Trenaunay-Weber syndrome.

Klippel Trenaunay-Weber syndrome is a complex developmental disorder characterized by a triad of cutaneous haemangioma, varicosities of the body, and unilateral limb hypertrophy. We describe the prenatal diagnosis of Klippel-Trenaunay-Weber syndrome at 15 weeks' gestation using the surface rendering technique of three-dimensional ultrasound. The vivid three-dimensional images of the affected fetus are invaluable in prenatal diagnosis and parental counselling.

[Klippel-Trenaunay-type syndromes]. / Les syndromes "type" Klippel et Trenaunay.

Seeing the diversity of the clinical look and of the subjacent malformations of the Klippel and Trenaunay Syndrome the following questions can be put forward: must the term KT be kept up? If not how to replace it? The mesoblastic sheet includes angioblastic, lymphoblastic and osteoblastic lineages. Each of them gives rise to malformations. All the malformations and all the signs and symptoms they generate may exist alone or mixed, the diversity of association is unlimited. Hence the syndromes too. They cannot be gathered under the sole term of KT. On the other hand to give each of them an eponym would lead to confusion. Therefore the author proposes to limit himself to the use of the term "type KT" when getting in touch with. Once the syndrome is investigated accurately it must be specified by the causal malformations, the associated malformations and the secondary troubles. It is the only way to be understandable and to allow statistical research.

The etiology of the Klippel-Trenaunay syndrome.

The etiology of the Klippel-Trenaunay syndrome (KTS) remains obscure. Although venous hypertension secondary to deep venous obstruction has been suggested as a cause, recent studies have demonstrated that most patients have unimpeded venous drainage. Calf blood flows have been measured in 33 patients with KTS using venous occlusion plethysmography. Although all flow rates were within normal limits, flow in affected limbs was invariably greater than in normal limbs (p less than 0.001), and this is related to the presence of the nevus. Biopsies of subcutaneous veins demonstrate the histological features of a response to chronically raised flow. The authors suggest that KTS is caused by mesodermal abnormality during fetal development, leading to the maintenance of microscopic arteriovenous communications in the limb bud, as a result of which the triad of nevus, hypertrophy, and superficial varices is produced. Deep venous abnormalities occur pari passu with the triad and are not responsible for its development.

[Klippel-Trenaunay syndrome and phacomatoses]. / Syndrome de Klippel et Trenaunay et phacomatoses.

Several mechanisms can be invoked in order to explain the appearance in a limb of the characteristic triad : naevus, varices and osteodystrophy. Many cases can be explained by the haemodynamic disturbance associated with venous hypertension caused by a venous malformation combined with arteriovenous microcommunications. These are the true Klippel and Trenaunay Syndromes. In a few rare cases the haemodynamic disturbance is caused by one or more arteriovenous fistulae with major flows. These are the Parkes-Weber-Syndromes. Finally, in the more complex syndromes there is the combined triad of naevus, varices and osteodystrophy, together with other genetic disturbances. These are the Phacomatoses.