Morphologic And Immunophenotypic Characteristics Of Intraductal Papillary Neoplasms Of The Breast

Purpose To investigate the morphologic and immunophenotypic characteristics of intraductal papillary neoplasms of the breast and explore the diagnosis criteria.Methods Fifty-five cases of intraductal papillary neoplasms of the breast were observed with hematoxylin eosin stain and studied by immunohistochemical method. Results⑴Twenty-eight cases of intraductal papilloma were confirmed as principal disease. They were characterized by an papillary structure composed of fibrovascular stalks coverd by a layer of myoepithelial cells with overlying glandular epithelial cells within a distended duct or ductule. Twenty of the 28 cases displayed usual epithelial hyperplasia, and 2 cases displayed less than 10% of the papillary processes with atypical epithelial hyperplasia. Glandular epithelial cells were moderate to strong positive for CK5 in 26 cases (92.9%), and for CK34βE12 in 25 cases (89.3%). Myoepithelial cells were positive for SMA, p63, CD10.⑵Six cases of atypical intraductal papilloma were confirmed. Three of the 6 cases were confirmed as concomitant disease and 3 case was confirmed as principal disease. They displayed at least 10% but less than 90% of the papillary processes with atypical epithelial hyperplasia.The epithelial cells with atypical hyperplasia were negative for CK5 in all, and negative to weakly positive for CK34β-E12 in 5 cases.⑶Twenty-four cases of intraductal papillary carcinoma were confirmed.①Bland IDPC were characterized by 90% or more of the papillary processes were totally devoid of a myoepithelial cell layer in 2 of the 24 cases.②Low grade IDPC occupied more than 90% of the lesion in 2 case。③Ten cases were characterized by both devoid of a myoepithelial cell layer and low grade.④Ten cases displayed moderate to high grade IDPC. Immunohistochemically, in the cases of②and③, CK5 was negative in all, and CK34βE12 was negative to weakly positive in 9 cases (75%). In the cases of④, CK5 and CK34βE12 were negative to weakly positive in 8 cases (80%). Conclusions Intraductal papillary neoplasms of the breast contain various benign to malignant lesions. Both the morphologic and immunophenotypic characterristics are different in the lesions, and the diagnosis must be made based on the above characterristics.