I was diaganosed with invasive in situ breast cancer . what is the in situ about?

Invasive VS in situ: Carcinoma in situ means pre-cancer condition- non invasive lesions that contains in the ducts or lobules of the breast. On the other hand, cancer is invasive neoplastic lesion of the breast . I am not clear to what you wrote- invasive in situ breast cancer?

Behavior of CA cell: ' in situ' means with in the confinement, ' ductal carcinoma in situ' means the cancer cell are confined to inside of ducts, cells are dormant ( sleepy ) , not spreading, confined to within basement membrane of the duct . If one area cells penetrate the membrane of the duct, and seen out side the duct means invasive, will be ready to spread, still a very early stage. Same for lobular carcinom.

ReviewPATHw/Surgeon: It is not uncommon to have in situ cancer next to invasive breast cancer. We stage the cancer based upon the size of the invasive component. However, the extent of in situ disease may impact our ability to do a lumpectomy vs. Mastectomy and may influence the type of radiation therapy that can be offered. I suggest you meet with your surgeon to review these details.

Two different kinds: You are describing two different things. An in situ breast cancer means it is non-invasive. There can be ductal and lobular types of in situ (non-invasive) breast cancer. An invasive breast caner is something different, meaning there is microscopic spread into the local breast tissue. In situ and invasive breast cancers may be treated differently. Review with your doctor.