There is a large round nucleus in the middle of the breast is considered to be due to physiological factors, pathological factors and other reasons, if symptoms occur, it is recommended to go to the hospital for examination and treatment in a timely manner to avoid triggering other symptoms. 1. Physiological factors: Everyone’s body in the breast will exist in the mammary glands, is a normal physiological structure of the breast tissue, manifested as clinical symptoms, no other symptoms of discomfort is no need to worry. If it is during puberty, then consider the development of breast nucleus. 2. Pathologic factors: (1) menstrual syndrome: when in the menstrual period, the body’s hormone secretion increased, manifested in the middle of the room there is a large round nucleus of the symptoms, in general, there is no need to worry about. (2) non-lactating mastitis: when the body’s milk ducts do not pass, resulting in milk being infected by bacteria as well as stagnation, so that inflammation of the breasts, manifested as clinical symptoms. (3) Mammary gland hyperplasia: When there are abnormalities in the body’s functions and endocrine disorders, the mammary glands will hyperplasia, which will show up as clinical symptoms, but if there are no other symptoms, no treatment is needed. (4) Breast cysts: When abnormal breast growth leads to inflammation of the breast, which is manifested by the symptom of a large round nucleus in the middle of the breast, it is necessary to go to the hospital for examination and treatment in a timely manner, so as to prevent the development of lesions. In addition, there is a large round nucleus in the middle of the breast should also consider malignant tumors and other factors, the patient can consult a doctor for examination to clarify the cause of the disease.