Adenomyoepithelioma with malignant transformation diagnosed by immunohistochemical analysis: case report / Adenomioepitelioma com transformações malignas diagnosticado por imuno-histoquímica: relato de caso

Adenomyoepitheliomas (AMEs) are rare breast lesions, which are characterized by the proliferation of epithelial and myoepithelial cells. They are circumscribed lesions, which can be clinically and mammographically detected. However, when they are indistinctly limited, differential diagnosis with malignant lesions becomes difficult. In this paper, we report a case of adenomyoepithelioma with malignant transformation of the myoepithelial component, a rare histological type that arises from the malignant transformation of epithelial, myoepithelial, or both elements. Its course and prognosis are uncertain. Mastectomy with sentinel lymph node biopsy followed by radiotherapy are the most effective treatment approaches.

Adenomioepiteliomas (AMEs) são lesões raras na mama, caracterizadas pela proliferação de elementos epiteliais e mioepiteliais. Clínica e mamograficamente apresentam-se como lesões bem delimitadas, que, quando assumem aspecto mal delimitado, tornam difícil o diagnóstico diferencial com lesões malignas. Relatamos um caso de AME com transformação maligna do componente mioepitelial, tipo histológico ainda mais raro, que surge da transformação maligna de elementos epiteliais, mioepiteliais ou ambos. Seu curso e seu prognóstico são incertos, contudo, mastectomia com pesquisa de linfonodo sentinela seguidos de radioterapia constituem a forma mais efetiva de tratamento.

Myoepithelial carcinoma arising in an adenomyoepithelioma of the breast: a case report of a rare entity.

Adenomyoepithelioma of the breast is a rare tumor. Malignant change arising in this lesion is infrequent and only a few cases have been reported. We discuss a case of a 56-year-old female presenting with a firm breast mass, which was interpreted as myoepithelial carcinoma arising in a background of adenomyoepithelioma, based on morphological and immunohistochemical studies. This case is being highlighted for its rarity and distinct morphological spectrum.