Limb hyperplasia: case report of an unusual variant of Klippel-Trenaunay syndrome and review of the literature.

Klippel-Trenaunay syndrome (KTS) is a rare disorder involving a triad of cutaneous capillary malformations (port-wine stain), varicose veins or venous malformations, and bony or soft tissue hyperplasia of an extremity. It is one of many heterogeneous disorders known as overgrowth syndromes that are characterized by either generalized or localized somatic overgrowth. Overgrowth syndromes each have unique clinical, behavioral, and genetic features, but some of these features overlap, causing diagnostic difficulty. Cutaneous manifestations, however, can be key to distinguishing the various syndromes. We present a patient with an unusual variant of KTS consisting of right upper extremity hyperplasia, lymphedema, and cutaneous and visceral lymphangiomas. We review several closely related syndromes and discuss the differential diagnosis of limb hyperplasia.