Cytological features of nipple adenoma in scraping smears.

INTRODUCTION: Nipple adenoma (NA) is a benign epithelial lesion of the breast that can clinically simulate Paget's disease or invasive ductal carcinoma. Therefore, correct pre-operative diagnosis is important for appropriate management. METHODS: Cytological samples may be obtained by different methods such as fine needle aspiration, nipple discharge or nipple scraping. Herein, the cytological features of three cases of NA are described in which samples were derived from nipple scraping. RESULTS: In all three cases, patients were adult females presenting with a sub-areolar nodule, showing skin ulceration in 2 of 3 cases. The nipple scraping cytological smears were characterised by a bloody background with epithelial cells arranged in clusters or singularly, showing an irregular nuclei profile. These features could simulate a malignant process. However, at higher magnification, fine nuclear chromatin with inconspicuous nucleoli and presence of myoepithelial cells were helpful to exclude malignancy. DISCUSSION: NA may present "worrisome" cytological features on smears derived from nipple scraping. Therefore, knowledge of the cytological spectrum of this lesion is important to avoid misdiagnosis.