ADH vs DCIS

What is the difference between ADH and DCIS. Aren't they both considered a "pre-malignant" stage?
Thank you for your time.

[CCF-RN,MSN-JS]

Dear Rfrancis, Atypical ductal hyperplasia (ADH) is an overgrowth of abnormal cells within the duct and is considered a risk factor not a pre-cancer.  Ductal carcinoma in situ (DCIS) is an overgrowth of cells with changes consistant with cancer but are contained within a duct of the breast, and is considered a pre-cancer.  DCIS if untreated, in time (and we don't know how much time) can progress to invasive cancer.  DCIS differs from invasive or infiltrating cancer in which the cells (in invasive cancer) show evidence of growing through the walls of the duct.  These conditions (ADH, DCIS, and invasive cancer) may occur independent of each other not necessarily in a progression of one to the other.

[schultzi]

A related discussion, When ADH turns into DCIS was started.

[joneal]

A related discussion, DCIS was started.