Papillomas of the breast. A histologic spectrum including atypical hyperplasia and carcinoma in situ.

We have illustrated intraductal papillomas that have a variety of alterations not found in "ordinary" or typical papillomas. Many of these changes are indistinguishable from ductal carcinoma in situ. A priori, one might expect that patients with papillomas associated with changes identical to ductal carcinoma in situ would be at an increased risk for subsequent invasive carcinoma. We suspect that there is an increased risk based on the fact that seven of our 26 cases (27 percent) had fully diagnostic ductal carcinoma in situ or invasive carcinoma in the breast. However, the degree of increased risk has not been definitely established.