图示乳腺导管中的小的良性导管内乳头状瘤，代表性地出现于乳晕下的一个主要输乳管内。值得注意的是上皮细胞未显示异型性且在乳头状瘤有清晰可见的粉红色胶原间质。导管内乳头状瘤可能产生浆液性或血性乳头溢液，也可能引起某种程度的乳头内陷。 A small benign intraductal papilloma appears here in a breast duct, typically in one of the main lactiferous ducts beneath the areola. Note that the epithelial cells show no atypia and that there is a fine pink collagenous stroma within the papilloma. An intraductal papilloma may be associated with a serous or bloody nipple discharge, or it may cause some nipple retraction.