What do hyperintense signals in breast mri mean?

Usually benign: Glandular tissue and cysts can do this and are most often seen when the MRI is done later in the menstrual cycle. Concerning findings are masses that get bright with contrast and have other features that suggest cancer.

Well you did not spe: Specify if this was before or after contrast. If you see an enhancing lesion - it can be benign but it might be malignant. It depends on the appearance - location and enhancement pattern. If your area has washout enhancement it makes it more serious. Hyperintense lesions on precontrast images are usually cysts and benign.

There is: not enough info to answer the question, because signal intensity varies depending on what particular MRI sequence is being performed, and whether or not IV contrast is used. For example, a benign breast cyst is hyperintense(bright) on a T2-weighted sequence, and hypointense(dark) on a T1-weighted sequence. A benign fibroadenoma may be hypointense on T1 without contrast, and hyper with contrast.