A mastectomy is a surgical procedure in which the entire breast is removed, typically as a treatment for breast cancer. There are different types of mastectomy procedures, and the extent of tissue removal can vary based on factors such as the stage of cancer, the size of the tumor, and the patient's overall health. The main types of mastectomy include:

1. **Total or Simple Mastectomy:** This involves the removal of the entire breast, including the breast tissue, nipple, and areola (the dark area around the nipple). The chest muscles beneath the breast are usually left intact.

2. **Modified Radical Mastectomy:** This procedure involves the removal of the entire breast, including the breast tissue, nipple, and areola, along with the removal of some of the lymph nodes in the underarm (axillary lymph nodes). The chest muscles are typically preserved.

3. **Radical Mastectomy:** This is an older and less common procedure where the entire breast, along with the chest muscles and all the lymph nodes under the arm, is removed. This type of mastectomy is now rarely performed, as less extensive procedures are often effective and associated with fewer complications.

4. **Skin-Sparing Mastectomy:** In this procedure, most of the skin over the breast is preserved, which can be important for reconstructive surgery. The breast tissue, nipple, and areola are removed, but the skin is left intact for immediate or delayed breast reconstruction.

5. **Nipple-Sparing Mastectomy:** This involves the removal of the breast tissue while preserving the breast skin, nipple, and areola. This type of mastectomy is often done with immediate breast reconstruction.

Mastectomy may be recommended when breast-conserving surgery (such as lumpectomy or partial mastectomy) is not a suitable option due to the size or location of the tumor, or if the patient chooses to undergo mastectomy for personal or medical reasons. After mastectomy, some women may choose to undergo breast reconstruction surgery to restore the appearance of the breast. The decision to undergo mastectomy and the type of mastectomy performed depend on the individual patient's circumstances and preferences, as well as the recommendations of the medical team treating the breast cancer.