Fast growth of breast lumps may be due to malignant lesions of breast lumps, inflammation of breast, benign breast tumors and so on. 1. Malignant lesions of breast lumps are usually characterized by hardness, adherence to skin, unclear boundary of the lump and rapid growth, which are mainly caused by accelerated growth and reproduction of cancer cells, and may be accompanied by nipple overflow and indentation. It is recommended that patients should consult doctors for tumor puncture test in time to confirm the nature of specific lesions. 2. Breast inflammation, mastitis patients may have hard lumps in one part of the breast with unclear boundary, and very few patients may have rapid growth of hard lumps. 3. Benign breast tumors. Some patients with benign breast tumors may also experience rapid growth of the lump, but it is less common. In addition, there may be other reasons for the rapid growth of breast lumps, which should be taken seriously, and patients should consult a doctor as soon as possible, complete the examination, and follow the doctor’s instructions to deal with it after clarifying the cause.