Polymorphous adenocarcinoma of the breast: A case report

We report a patient with polymorphous adenocarcinoma of the breast. Polymorphous adenocarcinoma of the breast is a rare tumour that corresponds to polymorphous adenocarcinoma in the salivary gland. The tumour consisted of a unimorphous population of one type of neoplastic cells with hyperchromatic, pleomorphic nuclei. Neoplastic cells were arranged in various architectural patterns including solid pattern, trabecular pattern and single “Indian-file“ arrangement with myxoid stroma in between. Tumour cells were negative for Estrogen, Progesterone, Her-2/neu, Smooth Muscle Actin, Cytokeratin 5/6, Cytokeratin 7, Synaptophysin and Chromogranin, while Cytokeratin AE1/AE3 (Pankeratin), BCL2 and E-cadherin were positive and p63 partially positive. Polymorphous adenocarcinoma is a rare and salivary gland-type tumour with only three cases reported up to date. To the best of our knowledge this is the fourth case of a polymorphous adenocarcinoma of the breast reported in the english literature.