An ultrastructural study of elastofibromas.

Two cases of elastofibroma were studied by light and electron microscopy. In both cases the lesion was located in the subscapular area; in one case the lesions were bilateral. By light microscopy the masses were seen to be unencapsulated and composed of dense collagen and numerous elastinophilic globules and fibers. Ultrastructurally the elastinophilic material frequently contained a central core of mature elastic tissue and appeared to be secreted by active fibroblasts. Unique dense granular bodies within the fibroblast cytoplasm are described, which are thought to represent elastin or elastin precursors. This study further substantiates the thesis that the elastic material in elastofibroma is derived from excessive production by fibroblasts rather than from elastotic degeneration of collagen as suggested by previous studies.