Spectrum of Papillary Breast Lesions According to World Health Organization Classification of Papillary Neoplasms of Breast.

Introduction Papillary breast lesions are segregated into benign and malignant based on the presence or absence of myoepithelial cells in the papillary cores. Papillary breast lesions are further classified into: intraductal papilloma, papilloma with atypical ductal hyperplasia (ADH)/ductal carcinoma in situ (DCIS), papillary DCIS, solid papillary carcinoma in situ, solid papillary carcinoma with invasion, invasive solid papillary carcinoma, encapsulated papillary carcinoma and encapsulated papillary carcinoma with invasion. In this study, we evaluated the spectrum of papillary breast lesions in resection specimens of the breast according to the latest World Health Organization (WHO) classification of breast tumors. Methods This was a retrospective cross-sectional study, and was conducted at Liaquat National Hospital for a period of six years, from January 2012 till December 2017. Data of patients that underwent surgeries for breast tumors were included in the study. All specimens were grossed, according to defined protocols, and representative sections were taken after inking resection margins. Hematoxylin and eosin-stained sections were examined by experienced histopathologists, and myoepithelial stains (p63 and myosin) were done in selected sections of all tumors. Histopathological classification of papillary tumors was performed according to WHO classification of breast tumors. Results The study involved 190 excision specimens of papillary breast lesions. Mean age of the patients was 45.6±17.1 years. Most of the lesions were between two and five centimetres (69.1%). For invasive carcinomas (n = 76), the most frequent grade was II (52.6%). For in situ and invasive carcinomas (n = 129), lymphovascular invasion and axillary metastasis were noted in 5.4% and 9.3% cases, respectively. Among papillary breast lesions, 36.8% were benign (intraductal papilloma, solitary or multiple) while 63.2% harbored ADH, DCIS, or invasive carcinoma. Invasive papillary carcinoma was the most frequent malignant papillary lesion (20%), followed by solid papillary carcinoma with invasion (12.6%). We found significant associations between patient's age and tumor size with histological type of papillary lesion as benign papillary lesions had smaller size and younger age compared to malignant papillary lesions. Conclusion We noted a high frequency of malignancy in papillary breast lesions. Moreover, malignant papillary lesions were significantly associated with higher age and larger tumor size.