Malignant adenomyoepithelioma of the breast: A case report

Abstract

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.

Figure 1

Mammography scan showing a 40 × 40 mm nodule with unclear margins and no calcification observed within the mass.

Figure 2

A, Immunohistochemical staining of the resected tissue. Positive calponin staining in myoepithelial cells (200 × magnification). B, Immunohistochemical staining of the resected tissue. Myoepithelial cells were very strongly positive for cytokeratin-5 (CK5) (100 × magnification). C, Immunohistochemical staining of the resected tissue. Nuclear P63 staining in the myoepithelial component confirmed differentiation of the myoepithelium (100 × magnification).