Question: What is the difference between ductal carcinoma in
situ (DCIS) and lobular carcinoma in situ (LCIS)? Answer: Ductal
carcinoma in situ refers to the cells that arise in the ducts of
the breast that are malignant in their own right. In other
words, if you were to look at them under a microscope, you could
say these are malignant cells, although ductal carcinoma in situ
does not act yet like other malignancies; it does not spread
past the breast. Now lobular carcinoma situ is a horse of a
different color altogether. It's probably not really a cancer
and it's been given the name by accident. Some of us even call
that lobular neoplasia so that we separate that from the word
carcinoma, which everyone understands to mean cancer. But
lobular carcinoma situ is a marker of a patient who is at risk
for developing a real cancer sometime in the future. We don't
really believe that the cells are malignant in their own right,
but they just predict that that patient has a higher chance than
her next door neighbor,