Possible cancerous change of intraductal papillomas of the breast. A 3-D reconstruction study of 25 cases.

Surgical specimens from 25 patients with intraductal papilloma were subjected to 3-dimensional (3-D) reconstruction studies of their mammary ducts. Papillomas of the multiple type (15 cases) always originated in the terminal duct lobular units (TDLU), whereas all papillomas of the solitary type (10 cases) originated in the large ducts except for one. In 6 of the 25 (24%) patients ductal carcinomas were accidentally found during specimen reconstruction. Two of the six patients harbored microscopic carcinoma as small as 3 mm or less. Three-D reconstructions revealed that carcinomas with multifocal origins in the TDLUs were connected with peripheral papilloma. Papilloma preceding carcinoma was of the multiple type in five patients, and of the solitary type in one. This study also showed that 6 of the 16 (37.5%) patients with papilloma originating in the periphery had carcinomas, whereas none of the nine patients originating in the center did. This observation strongly suggests that the peripheral papilloma is highly susceptible to cancerous change.