The pathogenesis of mammary gland lobular tumor is similar to that of mammary fibroadenoma, which is related to factors such as heredity, endocrine hormone disorders, and quantitative or qualitative abnormality of estrogen receptor contained in tumor cells. 1. Heredity: the development of breast lobular tumor is related to heredity and gene, the probability of occurrence of breast lobular tumor increases in the immediate family members who have breast lobular tumor, which suggests that this disease is related to heredity and gene, but the specific mode of inheritance and gene are not yet known. 2. Endocrine hormone disorders: Lobular tumor of mammary gland occurs in adolescent and childbearing age women, and the secretion of estrogen and progesterone in women’s body at this stage is easy to be imbalanced and cause endocrine disorders, which suggests that endocrine hormone disorders are an important factor in the development of Lobular tumor of mammary gland. 3. Abnormal quantity or quality of estrogen receptor contained in tumor cells: Lobular tumor of breast is often secondary to fibroadenoma of breast, and the abnormal quantity or quality of estrogen receptor in tumor cells leads to abnormal sensitivity to estrogen, which causes tumor growth. There are benign and malignant breast lobular tumors, patients should go to the hospital in time, complete the examination, clarify the nature of the tumor, and carry out regular treatment under the guidance of the doctor.