MUC1 and Poroma: Round or ovoid nuclei with clear cytoplasm and focal ductal differentiation can be seen in microscopic examination while no peripheral palisade presents.[1,2] Furthermore, there might be mitoses, but no cellular atypia can be found.[13] The poroma is characterized by epithelial membrane antigen and carcinoembryonic antigen positive and Ber-Ep4 negative.[2]