Prenatal ultrasonographic findings in Klippel-Trenaunay syndrome: A case report

BACKGROUND: Klippel-Trenaunay syndrome (KTS) is a rare congenital disorder. A detailed prenatal ultrasound examination plays an important role in the diagnosis of KTS and the subsequent counseling and follow-up of the patient. CASE SUMMARY: A 25-year-old woman attended our department for a regular examination. The whole of the right lower extremity and right buttock were observed to be markedly thicker compared to the left one at 18 wk of gestation. However, the lengths of the right femur, tibia and fibula were in the normal range. No marked edema and fluid/cystic spaces were detected in the lower limbs. There were no other organ abnormalities. The vasculature in the right limb was visibly dilated, with much higher intensive blood flow signals. No congenital embryonic veins were visible in both limbs. The right lower limb exhibited much more hypertrophy compared to the left limb two weeks later. Amniocentesis and genetic tests showed normal results with 46 XX. Despite the normal karyotype, the family opted to terminate the pregnancy. The post-mortem examination confirmed asymmetric hypertrophy of the right limb in the fetus and revealed a large area of marked dark-purple superficial capillary malformations occupying the skin of the right lower extremity. The enlargement of veins and soft tissue hypertrophy were also seen on postnatal X-ray and Magnetic Resonance Imaging. Autopsy revealed severe congestion in the right lower limb. A final diagnosis of KTS was made. CONCLUSION: KTS may be diagnosed prenatally based on the typical features observed during ultrasound examination.