Malignant adenomyoepithelioma of the breast: A case report.

RATIONALE: Adenomyoepithelioma (AME) is a rare biphasic tumor consisting of epithelial and Myoepithelial cell. Most of the AME is benign, and only a few will progress to malignancy, Here, we report a case of low-grade malignant adenomyoepithelioma, and review the related literature, in a bid to investigate its clinical and pathological features and thus, enhance our understanding of this tumor.

PATIENT CONCERNS: A 64-year-old woman visited our hospital with a 1-year history of a painless mass in her left breast. Physical examination revealed a palpable painless mass, measuring approximately 4.5 cm, in the left breast.

DIAGNOSIS: Histological examination confirmed the diagnosis of malignant adenomyoepithelioma.

INTERVENTIONS: The patient underwent local excision of the mass, with frozen section analysis revealing ductal carcinoma in situ. Mastectomy and sentinel lymph node biopsy were then performed.

OUTCOMES: We conducted a one-year follow-up, and relapse was not observed.

LESSONS: Treatment of AME remains controversial owing to the lack of high volume data and absence of prospective studies. Simple mastectomy is an acceptable treatment of this tumor.