Breast cancer, also called
malignant breast neoplasm, is a type of cancer originating from breast tissue.
Initially, breast cancer may not cause any symptoms.
The overwhelming majority of
cases in humans are women. Men can sometimes also develop breast cancer.
A tumor can be
benign or malignant. Breast cancer is a malignant
tumor (a collection of cancer cells) arising from the cells of the breast.
The causes of breast cancer are not yet fully known.
There are two main types of breast cancer:
- Ductal carcinoma. It affects the ducts that
move milk from the breast to the nipple. Most breast cancers are of this type.
They can be in situ or invasive.
- Lobular carcinoma, which starts in the lobules
that produce milk.
Symptoms of non-cancerous conditions like infection or a cyst are similar to
those of breast cancer.
The earliest breast cancers are
detected by a mammogram
(x-ray of the breast).
Most types of breast cancer are easy to diagnose by microscopic analysis of the
biopsy and lab exams.
Over time, cancer cells can invade nearby healthy breast tissue and get into the
underarm lymph nodes.