Objective: To investigate the clinicpathological features of atypical apocrine metaplasia in sclerosin adenosis of the breast. Methods: 1 case of atypical apocrine metaplasia in sclerosin adenosis of the breast was investigated, included clinical and pathological data, and analyzed their clinical manifestations, histological and immunohistochemistical features, and reviewed the literature. Results: There was a round hard mass located at 3 o’clock in the left breast, diameter about 1.7 cm. Multiple unequal round nodules were shown with sclerosis fibrous stroma. Atypical apocrine metaplasia cells occupied the region of >90%, cells arrangemented round or irregular glandular or the small nest, and the pink secretion in glandular cavity. The sharp of atypical apocrine metaplasia cells was irregular, with abundant granular eosinophilic cytoplasm, the nuclei was enlarged, round or slightly irregular, with thickening nuclear membrance. Most cells had 1 to 2 a large and prominent eosinophilic acid nucleolus. The mitosis was rare (2/50HPF). Atypical apocrine metaplasia cells were positive for CK, EMA, GCDFP-15, Ki67 index was 10%, negative for S-100, ER, PR, and HER2. Calponin and p63 showed myoepithelial cells around the gland. Conclusion: Atypical apocrine metaplasia in sclerosin adenosis is an uncommon breast lesion, identified with low-level apocrine ductal carcinoma in situ and invasive apocrine carcinoma by histological and immunohistochemistical characteristics.