Aims: To assess the accuracy of diagnosing papillary breast lesions in core needle biopsy.
Methods and results: One hundred biopsy specimens of papillary breast lesions were reviewed and compared with the final excisional diagnoses. The discordant biopsy specimens were stained for oestrogen receptor (ER), cytokeratin (CK) 14 and p63, and these specimens were reclassified based on these results. The overall core biopsy accuracy, false-positive and false-negative rate were 79%, 5% and 16%, respectively. A benign core biopsy specimen diagnosis gave a false-negative rate of 10%, and malignant core biopsy specimen diagnosis did not give any false-positive results. Using homogeneous ER (epithelial), positive CK14 (epithelial) and p63 (myoepithelial) immunoreactivity as benign criteria, the discordant rate was reduced by 30% and 69% when using all three or two of these three criteria for diagnosis. However, false-positive and -negative cases could not be totally eliminated.
Conclusions: Immunohistochemistry is helpful in core biopsy diagnosis of papillary breast lesions, but some cases remained misdiagnosed.