Macromastia is a condition in which one or both breasts develop excessively, resulting in an excessive increase in breast size. In general, a single breast volume of more than 1500mL is called gigantomastia. Patients can use two methods to measure breast volume: 1. by measuring the height, base and front width of the breast 2. Using a container filled with water, the breast is placed in the container and calculated based on the amount of water discharged. The doctor then needs to confirm the diagnosis based on the patient’s symptoms and examination, as follows: 1. Symptoms: The patient’s breasts are bulging, huge, and the skin is tense, often accompanied by shoulder and back pain, chest tightness in the lying position with breathing difficulties (respiratory distress). In addition, due to the persistent sagging of the giant breast, the skin of the inframammary fold rubs against the skin of the chest wall repeatedly and is impregnated with sweat, which easily causes local vesicular infection. 2, examination: need to perform breast ultrasound, MRI examination and breast tumor identification. Breast enlargement is often seen in adolescent girls or young women. Adolescent breast enlargement is often associated with high estrogen levels and abnormal sensitivity of breast tissue to hormones, while breast enlargement in young women may be due to obesity, pregnancy, and breast changes after breastfeeding. In addition, breast adenopathy can also lead to breast enlargement. Patients with breast enlargement, especially those with clinical symptoms such as shoulder and back pain and respiratory distress, should be treated with breast reduction surgery to remove some of the breast tissue and fatty tissue.