It is also called “subcutaneous mastectomy”. In more than 70% cases, gynecomastia is caused by a hypertrophic mammary gland. The breasts feel identical to real breasts. Tenderness or off-white nipple secretion is sometimes observed. A small periareolar incision is made to enter into the subcutaneous layer for breast tissue dissection and excision. On average, 90% of hypertrophic tissues need to be removed to make the breasts appear flat. However, some mammary gland tissues need to be kept to prevent breast concavity. If the breasts are saggy, a long inframammary incision is made to completely remove hypertrophic breast tissues and redundant skin.