Close to ninety percent (90%) of breast cancer are adenocarcinomas (ductal carcinoma) which arise from the cells of the ducts. There are about 30 different subtypes of ductal adenocarcinomas.

Ten percent (10%) of breast cancer are small cell carcinomas (lobular carcinoma) and are more likely to be found in both breasts.

Both ductal and lobular carcinomas can be in situ, self-contained, or metastasized.

Other, less common types of breast cancer include:

• Inflammatory breast cancer (Medullary carcinoma)
• Mucinous carcinoma (usually occurs in postmenopausal women)
• Paget disease of the nipple
• Phyllodes tumor (rarely metastasizes)
• Tubular carcinoma (small tumor often undetectable by breasts self-exam)

Sarcomas and lymphomas rarely develop in the breasts.

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