This is a invasive ductal carcinoma also known as a scirrhous carcinoma. Most of these cancers exhibit a a marked increase in dense, fibrous tissue stroma. These growths, as seen here, occur as fairly sharply delimited nodules with infiltrative attachment to surrounding structures. Note that the cancer has attached to the nipple, which caused nipple retraction. When scraped this tumor may produce a grating sound caused by small foci of calcification.
