Malignant adenomyoepithelioma of the breast:report of three cases and review of literature

ZHANG Xin; QI Yao; GAI Xiao-ying; WANG Shang; XU Jing

doi:10.3969/j.issn.1007-8096.2025.04.014

Abstract：Objective We present three cases of malignant adenomyoepithelioma(M-AME)of the breast and review 79 cases reported in the literature to broaden its morphological spectrum.Methods We conducted a retrospective analysis about three cases of M-AME of the breast from Qingdao Central Hospital of University of Health and Rehabilitation Sciences between 2020 and 2024 and summarize its clinical features.Results All three cases have two or three similar histological growth patterns.The first pattern was solid nests.The myoepithelial cells were located on the periphery of the cell nests,presenting as polygonal or spindle-shaped cells with clear or eosinophilic cytoplasm.There can be glandular epithelium with deeply stained cytoplasm inside the cell nests or not,with or without extracellular mucus.The second pattern is similar to＂microglandular adenosis＂,presenting small tumor cell nests mainly composed of cells with clear cytoplasm,scattered in the adipose and breast stroma.The third pattern shows that the tumor cells are arranged in elongated glandular ducts or appearing twisted shape in the collagen fiber,similar to ＂low-grade adenosquamous carcinoma＂.In addition,a region of well and medium differentiated squamous cell carcinoma is observed in the second case,and a region with a ＂papilloma-like＂ growth pattern is seen in the third case.Immunohistochemistry of the three cases all show negative expression of estrogen receptor(ER),progesterone receptor(PR),and human epidermal growth factor receptor 2(HER2).Conclusion M-AME of the breast has a diverse morphology.Understanding its morphological spectrum can improve the awareness of pathologists about the disease and provide a basis for clinical treatment.