What is the primary diagnostic tool for Paget's disease of the breast?

Mammography is the primary diagnostic tool for Paget's disease of the breast due to its ability to detect abnormalities in breast tissue. This non-invasive imaging technique is highly sensitive and can identify lesions and calcifications that may indicate underlying breast cancer. Paget's disease, which primarily involves the nipple and is often associated with underlying ductal carcinoma, can manifest as changes in the skin, discharge, and other visible signs that a mammogram can help assess.

In the context of Paget's disease, mammography can reveal associated masses or abnormalities in the breast that warrant further evaluation. It is the preferred initial imaging modality because it can provide comprehensive screening, making it easier for healthcare providers to identify any tumors present in conjunction with the symptoms observed.

Other imaging modalities like CT scans and PET scans are usually reserved for different contexts, such as staging cancer or evaluating for metastasis, and do not serve as the first-line diagnostic tool for Paget's disease. Ultrasound may be used as an adjunct to mammography for further evaluation but is not sufficient as a standalone or primary diagnostic method. This comprehensive understanding of mammography's role highlights its importance in diagnosing Paget's disease of the breast.