What is invasive ductal carcinoma?

➢ All carcinomas that cannot be subclassified into one of the specialized types ILC/Ca with medullary features/mucinous/tubular/inflammatory ➢ A majority (70%–80%) of cancers falls into this group. ➢ usually is associated with DCIS. ➢ The microscopic appearance varies, ranging from tumors with well-developed tubules and low-grade nuclei to tumors consisting of sheets of anaplastic cells. ➢ Most invasive ductal carcinomas produce a desmoplastic response, which replaces normal breast fat (resulting in a mammographic density; and eventually leads to the appearance of a hard, palpable irregular mass. ➢ About 50% to 65% of ductal carcinomas are ER positive, 20% are HER2 positive, and 15% are negative for both ER and HER2.