“…Histologically, NA can appear similar to other breast conditions (including syringomatous adenoma of the nipple, intraductal papilloma, adenomyoepithelioma, ductal carcinoma in situ, and invasive ductal carcinoma) as well as several dermatologic lesions (including syringoma of the skin, hidradenoma papilliferum, and syringocystadenoma papilliferum) [ 2 , 15 , 23 , 26 , 52 , 118 , 131 ]. The major histologic features of NAs are that they represent a ductal proliferation of glandlike structures within the stroma of the nipple, and generally have fairly well circumscribed borders but without encapsulation [ 8 , 15 , 23 , 26 , 52 , 118 ]. Sclerosis/fibrosis may distort glands, mimicking an invasive growth pattern.…”