A high-density lump in the upper outer quadrant of the breast is usually caused by a space-occupying lesion with calcification, which may be breast fibroadenoma, cystic hyperplasia of the breast or breast cancer. 1. Breast fibroadenoma: mostly solitary, except for the lump, no obvious conscious symptoms, not related to menstrual cycle, imaging examination found that the edge of the smooth and neat ovoid, round lump, density of nearly normal or high density, the lump can be seen around the thin layer of halo ring. 2. Breast cystic hyperplasia: it is excessive hyperplasia of breast parenchyma and incomplete regeneration caused by the imbalance of the ratio of estrogen and progesterone, and it can be found that one or both breasts are swollen and painful and have lumps, and the imaging examination can see that the hyperplastic tissues are in the form of nodules with density slightly higher than that of the surrounding glands. 3. Breast cancer: early on, painless small lumps may appear in the breast, hard, with non-smooth surface, and irregular, rough edges and high density shadow can be seen on imaging examination. At the same time, the high-density lump in the upper outer quadrant of the breast may also be calcified foci of breast tuberculosis and enlarged lymph nodes, etc. The diagnosis should be further clarified. Further diagnosis is needed. When a lump is found in the breast, you can go to the hospital in time, and according to the clinical manifestations and imaging examination, after clarifying the cause of the disease, targeted treatment.