Papillary tumors of large lactiferous ducts. 
The breast pathology files at the Institut Gustave-Russy in Villejuif, France, were searched for papillary cystadenomas and papillary carcinomas diagnosed between January 1, 1960, and December 31, 1974.  A total of 158 cases were selected for this study; they were subclassified into 74 papillary cystadenomas, 63 papillary carcinomas, and 21 multiple papillomas.  Spontaneous nipple discharge was the primary reason for consultation in 88% of solitary cystadenoma patients, 48% of multiple papilloma patients, and 23% of the carcinoma patients.  The data support the benign nature of papillary cystadenoma inasmuch as none of the 73 patients treated with local excision developed cancer of the same breast, with only one patient having recurrence of the lesion.  In contrast, multiple papilloma was associated with a high recurrence rate and malignant transformation.  According to Scarff and Bloom's grading system, papillary carcinoma was found to be of low grade malignancy with a five-year survival rate of over 90%.