Lobular cystic sarcoma refers to lobular cystic sarcoma of the breast, also known as giant fibroadenoma. According to the degree of cell differentiation and clinical manifestations, it can be classified as benign, low malignant and malignant, and most of them are clinically benign, and very few of them are malignant. Physical examination shows that the tumor foci are many and large, and in severe cases, they can occupy the whole breast, with uneven surface, tough texture, good mobility, and a few of them have pressure pain. It can be diagnosed and differentiated by pathological examination, molybdenum X-ray, ultrasound, arterial and breast subcutaneous venography and other related auxiliary examinations. The treatment of lobular cystic sarcoma of breast is based on surgical excision, and the prognosis is generally good after complete excision. If the patient feels obvious discomfort, it is recommended to go to the hospital immediately for examination and treatment.