A case of tubular adenoma of the breast mimicking cytological features of adenomyoepithelioma

Abstract

We report a case of a 77-year-old woman with tubular adenoma of the breast mimicking cytological features of adenomyoepithelioma. Fine needle aspiration revealed many clusters of ductal epithelial cells mixed with myoepithelial cells. Polygonal cells with abundant cytoplasm and psammoma bodies were also found. Histological examination disclosed glandular structures outlined by round to polygonal cells with clear cytoplasm. The glandular components surrounded by hyalinous stroma often contained psammoms bodies. There was no area of monotonous growth of tumor cells with clear cytoplasm devoid of glands. Immunostaning demonstrated distinct reactions for two cellular components. Epithelial cells were positive for epithelial membrane antigen and cytokeratin, whereas myoepithelial cells were reactive with alpha-smooth muscle actin. Based on these findings, the present case was diagnosed as tubular adenoma with focal proliferation of myoepithelial cells.