Adenomyoepithelioma of the breast: a review stressing its propensity for malignant transformation

Abstract

This review describes the classification, clinical presentation, pathological features and clinical behaviour of adenomyoepithelioma (AME) of the breast. It is based on an extensive review of the literature and study of a collection of cases built up over a 17-year period at the British Columbia Cancer Agency. The diversity of the morphology encountered in both benign and malignant AME is described. The behaviour of malignant AME seems to be related to the grade of the malignant component.

A clinical dilemma: malignant adenomyoepithelioma of the breast – case report and review of literature

“…[2] On mammography, AME appears as a round or lobulated, dense, mostly circumscribed mass, sometimes with partially indistinct margins. [7] The diagnosis of AME on a needle core biopsy can be challenging because of the morphologic heterogeneity. In limited biopsy material, the sampled tissue may even be mistaken for invasive carcinoma, especially in tumors that have compact glandular structures with clear cell epithelioid myoepithelial proliferation.…”

“…[15] Based on the differentiation of the malignancy, the tumors can be divided into monophasic and biphasic. The monophasic malignancy could be invasive ductal carcinoma not otherwise specified, metaplastic carcinoma, low-grade adenosquamous carcinoma [7] invasive lobular carcinoma, [16] and ductal carcinoma in situ, [17,18] arising from epithelial component, or malignant myoepithelioma [19] arising from myoepithelial component. Only 16 biphasic malignant AMEs in which malignancy arising from both epithelial and myoepithelial cells have been reported previously.…”

“…Only 16 biphasic malignant AMEs in which malignancy arising from both epithelial and myoepithelial cells have been reported previously. [6,7,11,20,21] Loose et al [4] have proposed a high mitotic rate, cytologic atypia, and infiltrative peripheral border as predictors of malignancy.…”

“…The role of surgery to the axilla is less well defined, with observation to axillary sampling and axillary clearance been proposed. [6][7][8]15] Axillary lymph node involvement is thought to be unusual; hence a recent review article has suggested that axillary node dissection is not indicated unless there are clinically involved lymph nodes. [8] The response to chemotherapy and radiotherapy is unknown.…”

“…Metastasis, only documented in tumours 2.0 cm or larger, appear to be hematogenous rather than lymphatic. [4][5][6][7][8] The best predictor for local recurrence is the surgical margin. Negative margins reduces local recurrence rates, there is no consensus on what constitutes an adequate negative margin.…”