Inverse Klippel-Trenaunay syndrome: review of cases showing deficient growth.

Background: Klippel-Trenaunay syndrome is defined by a coexistence of nevus flammeus and overgrowth of one or more limbs. Remarkably, however, deficient growth of an affected limb may likewise be noted.

Observations: We collected from the literature a number of cases of Klippel-Trenaunay syndrome associated with deficient growth such as shortening or hypoplastic muscle mass of the affected extremity.

Discussion: The cause of the unusual deficient growth is unknown. Some patients may be compound heterozygotes carrying a 'plus' and a 'minus' allele at the responsible gene locus, and postzygotic recombination would give rise to two different cell clones homozygous for either allele.

Conclusion: In order to give a name to such paradoxical cases, we propose the term 'inverse Klippel-Trenaunay syndrome'.