Elastosis in breast carcinoma: I. Immunohistochemical characterization of elastic fibres.

Elastosis associated with invasive ductal and lobular carcinomas of the breast was examined by tinctorial and immunohistochemical staining methods, enzyme digestion, and electron microscopy. The elastotic material exhibited the tinctorial staining properties of elastic fibres, and the ultrastructural appearances were those of elastic fibres although there was a higher proportion of microfibrils than in normal mature elastic fibres. The elastosis was immunostained by antisera to human fetal elastin, lysozyme and amyloid P component, as in other sites where elastic fibres are found. These findings indicate that immunohistochemically intact elastic fibres are present in the elastosis of breast cancer. They also demonstrate that lysozyme and amyloid P component are co-distributed with elastic fibres in elastosis of breast carcinoma, as distinct components with different susceptibilities to enzyme digestion. The cellular origin of elastosis in breast carcinoma remains uncertain.