MRI accurately depicts underlying DCIS in a patient with Paget's disease of the breast without palpable mass and mammography findings.

Breast-conserving therapy must be carefully indicated among patients with Paget's disease of the breast, because the disease is often associated with an underlying in situ or invasive carcinoma, even when there are no palpable mass or mammography findings. We report a 52-year-old woman who complained of skin color change of her right nipple for 11 months. No mass was palpable in her breasts, and mammography did not show any density or calcification. Nipple biopsy revealed Paget's disease of the breast with ductal carcinoma in situ (DCIS) in the breast epithelium just beneath the nipple. Magnetic resonance imaging (MRI) of the breast demonstrated diffuse segmental enhancement in two different quadrants. According to the pattern of enhancement, the lesions depicted by MRI were diagnosed as an extensively spreading type of DCIS. Based on informed consent, the patient received a total mastectomy. The histopathological examination demonstrated non-invasive ductal carcinoma with comedo-necrosis. The histological mapping with subserial sectioning demonstrated an extent of the lesions that corresponded accurately to the lesions defined by MRI. We conclude that MRI may play an important role in selecting candidates for breast-conserving therapy out of those patients with mammary Paget's disease with no clinical evidence of an underlying breast carcinoma.