Elastic fibers in dermis of juvenile elastoma.

To explore the ultrastructure of elastic fibers in juvenile elastoma, three patients (two without osteopoikilosis and one under examination of bones and joints) were studied by routine electron microscopy. In addition to normal elastic fibers, all the patients also exhibited alterations in elastic fibers. The altered ultrastructures showed lucent, homogenous matrix without peripheral microfibrils. The homogenous matrix were seen in various extensions from the small protrusions of the normal elastic fibers to the complete replacement of the entire fibers. Collagen fibrils occasionally showed twisted figures. Normal shapes of dermal glycosaminoglycans were increased in number. It seems likely that the lucent, homogenous matrix without peripheral microfibrils are the characteristic changes of elastic fibers in juvenile elastoma. The alteration could be nevoid in nature.