Mastocytosis belongs to the category of “breast fetish” in traditional Chinese medicine, and is a common non-inflammatory and non-tumor disease of women’s breasts, with breast lumps and swelling pain as the main symptoms, mostly related to menstruation and emotional changes, commonly seen in young and middle-aged women. Western medicine believes that mastocytosis is related to ovarian dysfunction, such as a decrease in luteinizing hormone secretion and a relative increase in estrogen secretion. Its incidence accounts for the first place of breast diseases. In recent years, the incidence of the disease has been increasing year by year, and the age is getting younger and younger. A 9-year-old girl with cystic hyperplasia of the breast was seen in the clinic. The main clinical manifestation is the appearance of single or multiple lumps in different parts of the breast, with unclear borders, movable, and often accompanied by varying degrees of pain. Especially before menstruation, after exertion, or during mood swings such as anger, the lumps increase in size and the pain worsens, while after menstruation the lumps shrink significantly and the pain decreases. Common symptoms Breast swelling and pain: the degree varies, the lighter ones are not bothered by the patient, the heavier ones can affect work and life. Early breast swelling and pain is characterized by a cyclical nature, occurring frequently or worsening in the premenstrual period, with no obvious regularity of pain after the disease progresses. Breast lumps: they are often multiple and can be seen on one side or both sides; they can be confined to a part of the breast or scattered over the whole breast. In addition, a few patients may have nipple discharge, which is yellow-green, brown, or occasionally colorless plasma. The physical examination of the breast is mainly done by visual and palpation to check the morphology of the breast, the condition of the skin surface of the breast, the condition of the nipple areola, breast lumps, nipple overflow, etc. Finally, do not forget the regional lymph node examination and the whole body examination. (1) Breast morphology: The appearance, size and position of the breast should be checked for symmetry. (2) Skin surface of the breast: The color of the breast skin and the presence of edema, rash, ulceration, superficial venous anger, dimple sign and orange peel-like changes should be checked. (3) Nipple areola: check for nipple deformity, elevation, retraction, depression, erosion and desquamation; eczema-like changes, etc. (4) Breast lumps: The correct breast examination should be done by touching the palm of the hand with four fingers together, using the most sensitive index, middle and ring fingers to lightly touch the outer upper and outer breast, the inner lower and inner upper area and finally the nipple and areola area in the middle of the breast in order. You should not use your fingers to pinch the breast tissue during the examination, otherwise the breast tissue that you pinch may be mistaken for a lump. The location, shape, size, number, texture, surface smoothness, mobility and tenderness of the breast lumps should be examined. The examination is mainly done by palpation. Generally speaking, bilateral multiple lumps with periodic breast pain are more likely to be benign, while unilateral single painless lumps are likely to be malignant. (5) Nipple overflow: check whether the nipple is overflowing, and check whether it is spontaneous or extruded, unilateral or bilateral, and the nature of the overflow. (6) Regional lymph nodes and general condition: Since breast cancer is prone to axillary and supraclavicular lymph node metastasis, physical examination of the breast should routinely check the size, texture and activity of the lymph nodes in these areas.