Linear focal elastosis. An ultrastructural study.

We studied an 86-year-old Japanese man with linear focal elastosis. The lesions were asymptomatic yellow striae in the lumbar region, histologically composed of massive, well-demarcated basophilic fibers that stained positively with elastic tissue stains. Electron microscopy revealed fine, reticular or granular electron-dense materials, and elastic fiber microfibril-like materials in the matrix, in addition to numerous mature and immature elastic fibers. These findings suggest that active elastogenesis was occurring in the lesions. The four cases reported so far have the three common features of age, sex, and lesion location.