Abstract:

Objective To observe the morphological changes and significance of apocrine metaplasia with atypia in breast lesions. Methods The pathological sections of 190 cases of invasive breast cancer and 48 cases of breast benign lesions were retrospectively analysed between January 2011 and September 2012, the morphological characteristics of apocrine metaplasia were observed under microscope, and gross cystic disease fluid protein-15 kDa (GCDFP-15) and androgen receptor (AR) were determined by immunohistochemical staining. Results Apocrine metaplasia exhibited cystic, papillary and atypical type under microscope. There were 40 cases of apocrine metaplasia in invasive cancer, including 28 cases of cystic type, 4 cases of papillary type and 8 cases of atypical type. There were 13 cases of apocrine metaplasia in breast benign lesions, including 9 cases of cystic type, 2 cases of papillary type and 2 cases of atypical type. There was no significant difference in the incidence of apocrine metaplasia between cases of invasive cancer and those of breast benign lesions (P>0.05). Apocrine metaplasia of atypical type accounted for 4.2% (8/190) and 4.2% (2/48) in cases of invasive cancer and those of breast benign lesions respectively, and accounted for 20.0% (8/40) and 15.4% (2/13) in cases of invasive cancer with apocrine metaplasia and those of breast benign lesions with apocrine metaplasia respectively. Immunohistochemical staining revealed that the expression of GCDFP-15 and AR was positive in apocrine metaplasia. Conclusion Apocrine metaplasia extensively exists in the benign and malignant lesions of the breast, and can be identified by expression of GCDFP-15 and AR. Though no significant difference is found between invasive breast cancer and breast benign lesions, apocrine metaplasia of atypical type has the risk to develop into breast cancer, which should be attached great importance.

Key words: invasive breast carcinoma, apocrine metaplasia, apocrine metaplasia with atypia, gross cystic disease fluid protein-15kDa, androgen receptor