Proteus syndrome: report of the first Japanese case with special reference to differentiation from Klippel-Trenaunay-Weber syndrome.

This is the first report of a Japanese girl with Proteus syndrome. She presented with growth acceleration and precocious development of the left breast as well as macrodactyly, hemihypertrophy, a subcutaneous preaxillary mass, portwine stains, connective tissue nevi, and a depigmented macule. All these abnormalities were confined to the left side of her body. Although most of the manifestations fit those of Proteus syndrome, the presence of the portwine stains and hemihypertrophy also suggested Klippel-Trenaunay-Weber syndrome. The findings in our patient suggest that the most important characteristic distinguishing Proteus syndrome from Klippel-Trenaunay-Weber syndrome is the presence of functional abnormalities such as a growth spurt and precocious breast development. Proteus syndrome may be genetically different from the Klippel-Trenaunay-Weber syndrome.