Malignant adenomyoepithelioma of the breast with lymph node metastasis: a detailed immunohistochemical study

Abstract

Malignant adenomyoepithelioma of the breast is a rare tumour with around 30 cases reported in the literature. Metastases associated with these tumours are usually haematogenous. Axillary lymph node metastases are thought to be unusual, and it has been recently suggested that axillary node dissection is not indicated unless clinically palpable. We here present a case of a 63-year-old woman, who developed a malignant adenomyoepithelioma with axillary lymph node metastasis, that included epithelial and myoepithelial elements, in spite of the absence of clinically enlarged nodes. We suggest that histological examination of axillary sentinel node(s) or node sampling may be worthwhile in this condition.

Figure 1

Benign adenomyoepithelioma part of the lesion stained with smooth muscle actin to show the myoepithelial component stained brown.

Figure 2

(a) Malignant component: solid area stained with H&E showing dual-cell population with marked nuclear pleomorphism. (b) Malignant component: invasive edge of the lesion stained with cytokeratin 5.

Figure 3

(a) Lymph node metastasis: CK5 staining both epithelial and myoepithelial elements. (b) Lymph node metastasis: CK19 staining epithelial element. (c) Lymph node metastasis: smooth muscle actin staining myoepithelial element.