Cancer Stories

Breast Cancer Classification

August 26th, 2005

Classification
Breast cancer is a heterogeneous (origination from self) disease in terms of its clinical course, gross and microscopic pathology, and imaging characteristics.
Several histologic classifications exist. One example is the World Health Organization (WHO) classification, which divides breast cancers into noninvasive type, (in situ), invasive type, and Paget disease of the nipple.

In situ carcinoma is characterized by growth within the ducts without penetration of the basement membrane. In situ carcinoma is subdivided into ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS).

Invasive carcinoma denotes neoplastic penetration of the basement membrane of a duct containing DCIS and extension of neoplastic cell aggregates into the mammary stroma. It is further subdivided into these types:

1. ductal, which accounts for about 75% of all invasive breast cancers.
2. medullary
3. mucinous, or colloid
4. papillary
5. tubular
6. adenoid cystic carcinoma
7. carcinoma with metaplasia.

Paget disease of the nipple is a type of breast cancer that starts in the breast ducts and spreads to the skin of the nipple and then to the areola. It is rare, accounting for only 1% of all breast cancers. Paget disease may be associated with in situ carcinoma or with infiltrating breast carcinoma. If no lump can be felt in the breast tissue, and if the biopsy shows DCIS but no invasive cancer, the prognosis is excellent.

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