[A case of breast carcinoma, possibly the result of malignant transformation of an intraductal papilloma in a 26-year period].

A 74-year old female presented a giant tumor and serosanguineous nipple discharge from the left breast. The tumor was first recognized 26 years ago, and untreated. The resected breast contained several cysts and some small white nodules. Some of the cysts contained intracystic tumors. Histologically, the tumor consisted of a mixture of papillotubular carcinoma and intraductal papilloma. This case seems to represent a malignant change in intraductal papilloma from its long clinical course and by the microscopic findings. Review of this case seems to warrant clinical attention to the possibility that benign intraductal papilloma may transform itself into malignancy after many years.