Breast cyst category 3 is not necessarily cancerous. Breast cysts are benign lesions with a relatively low likelihood of becoming cancerous. Breast cyst category 3 in the clinic generally refers to breast occupying lesions, usually benign breast lesions, the chance of malignant lesions is relatively small. category 3 refers to the ultrasound or X-ray classification criteria, generally used to help determine the benign or malignant nature of the swelling. If the patient is more concerned, the cyst can be biopsied, and the biopsy can accurately determine whether the cyst is malignant. Breast cysts are cystic deposits in the breast. Breast cysts may be single or multiple, and are usually small and watery on palpation. A few cysts are hard, and in most cases they are benign and do not require treatment. The cysts are filled with fluid. If the cysts are large, they can also be treated by surgical excision or puncture aspiration. The chances of a category 3 breast cyst being cancerous are relatively small. If you are more concerned, it is recommended that you have a further examination to determine the nature of the cyst.