The pathology of congenital localized gigantism.

Two cases of congenital localized gigantism are described. They illustrate a form of segmental limb disproportion, characterized pathologically by an excessive linear growth of the skeletal structures and by soft tissue lipomatosis. The gigantism was confined to bones of the right great toe and adjacent metatarsus in one case; it affected the long bones of a lower extremity in the second case. Case 2, followed for over 7 years, developed a fibrovascular hamartomatous neoplasm of rapid growth and some cytological atypia in infancy--but this was well controlled by conservative surgery. This type of gigantism of the limb appears to be compatible with a normal life expectancy, and it is conceptually useful to distinguish it from hemihypertrophy. The number of cases reported is insufficient to support a significant association of gigantism with malignant tumors or with other life-jeopardizing anomalies.