Syndrome de Klippel-Trenaunay : identification d’un gène de susceptibilité codant pour un facteur angiogénique

Idiopathic corporeal hemihypertrophy associated with hemihypertrichosis

The hemihypertrophy or hemihyperplasy is a rare congenital abnormality, characterized by an asymmetric growth of the limbs, the trunk, and the face or half of the entire body. It may be isolated or be part of several syndromes including Beckwith-Wiedemann syndrome, Klippel-Trenaunay-Weber syndrome, Silver-Russell syndrome and Proteus syndrome. In its isolated form, it is called idiopathic. The latter may be associated with several anomalies including dermatological and urogenital abnormalities with increased risk of developing embryonal tumors. We report the case of a 22-month-old infant, who was referred by his pediatrician at the age of 15 months for a corporeal hemihypertrophy associated with hemihypertrichosis. In his medical history, a second degree parental consanguinity and a hypospadias in the father and a paternal uncle were found. Clinical examination found a weight and a size greater than chronological age (3 standard deviations), a hemihypertrophy of entire left side with a difference of length and diameter between the left and right limbs of 2 cm. The hemihypertrichosis was widespread in the left body and the genital examination found a hypospadias. Biological and radiological assessments did not show any abnormality, with the exception of an initially high plasma testosterone level, which gradually normalized. Thus, the diagnosis of idiopathic hemihypertrophy with congenital hemihypertrichosis was retained. This is the fourth case reported in the literature. Its management is similar to all hemihypertrophies, which consists of an initial assessment to detect an embryonic tumor, followed by a monitoring protocol including an abdominal and renal ultrasound every 6 months until the age of 8, determination of alpha-feto-protein every 6 to 12 weeks until the age of 4 years to track the development of the two most frequent tumors: Wilms tumor and hepatoblastoma. The hemihypertrophy associated with hemihypertrichosis has been exceptionally reported and the cause of this association has not been identified to date.