There is described fifty-year-old woman with so called malignant adenomyoepithelioma of thebreast. The conventional benign looking adenomyoepithelioma with biphasic tubular patterncontinually fused to unequivocal invasive lesion which by immunophenotype turned out to bemyoepithelial carcinoma. The 15 months follow up was uneventful. Extensive literature overviewand terminology consideration is presented. The paper discusses biologic consequences of thisrare breast lesion and its close resemblance to almost identical lesions in the salivary glands andskin adnexa.