Myoepithelial changes in solid papillary carcinoma of the breast

WU Huan-wen; LIU Xu-guang; LI Jun-jie; WANG Jing; ZHANG Hui; PANG Jun-yi; LIANG Zhi-yong

doi:10.3969/j.issn.1007-8096.2017.12.003

Abstract：Objective To investigate the roles of myoepithelial markers in the differential diagnosis and invasion recognition of solid papillary carcinoma (SPC) by studying the presence and distribution of myoepithelium both within papillae and at the periphery.Methods A total of 23 cases of SPC were retrospectively retrieved from surgical pathology files at the Peking Union Medical College Hospital from May 2014 to February 2017,and were studied by histopathological examination and immunohistochemical staining with a review of the literature.Results Among 23 cases of SPC,the presence of myoepithelium was observed in 18 cases (78.3％) both within papillae and at the periphery.12 cases (52.2％) and 6 cases (26.1％) had almost complete and partial myoepithelial layer,respectively,whereas only 5 cases (21.7％) completely lost myoepithelium.However,compared with adjacent normal ducts/lobules,the number of myoepithelium was significantly decreased in SPC,which was demonstrated by an increase in the internuclear distance between neighboring ME cells.There was good consistency between p63 and CK14 immunohistochemical staining for myoepithelium.The neoplastic cells in all of our SPC cases were negative for CK5/6 staining,but positive for at least one neuroendocrine marker.Conclusion The complete or partial presence of myoepithelium can be observed both within papillae and at the periphery in SPC.All SPC cases with the presence of myoepithelium demonstrate an increasing in the internuclear distance and a reduced number of myoepithelal cells.The presence or absence of myoepithelium is not essential for the differential diagnosis between SPC and usual ductal hyperplasia (UDH) involving a benign papilloma and the invasion recognition of SPC.