INFILTRATING DUCTAL CARCINOMA
This is the most common breast malignancy, accounting for 80% of breast
cancers. Most are unilateral and start as atypical ductal hyperplasia, which may
progress to ductal carcinoma in situ (DCIS), which then may break through the
basement membrane and progress to invasive ductal carcinoma. Over time the
tumor will become a stony hard mass as it increases in size and undergoes a
fibrotic response.