Clinicopathologic Analysis of Encapsulated Papillary Carcinoma of Breast

Objective To investigate the clinicopathological characteristics, diagnostic criteria, treatment and prognosis of encapsulated papillary carcinoma(EPC) of the breast. Methods We reviewed the clinicopathological information and immunohistochemical staining results of 35 cases of breast intracystic papillary carcinoma/EPC and 48 cases of intraductal papillary carcinoma used as controls. All cases were collected from Xinjiang Medical University Affiliated Cancer Hospital from January 2010 to December 2013. Results All 35 cases of EPC were females, and ages ranged from 29 to 83 years old, with a mean age of 61 years old. The average size of tumors was 2.4cm(0.6-4cm). Among the 35 EPCs, 22 EPCs were of pure type, 7 EPCs with ductal carcinoma in situ(DCIS), 4 EPCs with microinvasion(MI) and 2 EPCs with non-specific invasive carcinoma(IC). Myoepithelial cell staining was negative for CK5/6 and p63 within all cases of EPC and intraductal papillary carcinoma. At the periphery of the tumor nodules, the number of myoepithelium was obviously reduced in 35 EPCs compared with 48 intraductal papillary carcinomas, and the difference was statistically significant(P<0.05). 80% EPCs were positive for hormone receptor, 5.71% EPCs showed +++ staining for HER2. Eight patients(22.86%) underwent lumpectomy and 27 patients(77.14%)received mastectomy; 3 patients(8.57%) had lymph node metastasis. Followed up for 2-40 months after operation, all patients were alive. Conclusion EPC generally occurs in older women; myoepithelial cells are significantl y reduced and even entirely absent at the periphery of tumor. Lymphatic metastasis may be observed in pure EPC. EPC can be regarded as an indolent invasive carcinoma, which is intermediate in nature between DCIS and IC. For the patients with pure EPC or EPC accompanied by DCIS, MI should generally be treated as DCIS; those with EPC accompanied by IC should be treated as IC.