I read the discussion above carefully. This is a very interesting case. Agree with most of you. The differential diagnoses are florid ductal hyperplasia or UDH and ADH. No typical features of DCIS are present. DCIS should not be considered in this case. The process of UDH-ADH-DCIS is continuous. We are arbitrary to divide them into the different groups. So there are some gray zones. I would call this case as ADH, based on the proliferative cells show focal monotonous in some photos. This is a borderline case. If we show the case to 10 world breast experts, I am sure the answers will be different. Other factors also can affect your diagosis. If this is a breast core biopsy, I will be easy to call ADH. The patient will have an excisional biopsy to see if cancer is present in the adjacdnt breast tissue. If this is an excisional biopsy specimen, I will think more what I should call. We as pathologists should know the priciple for diagnosis.  For some borderline cases we do not need to try to figure out the diagnosis, becase no one knows exactly. Agree with Dr Stevenshen that IHC stains are not useful in the differential dx of DCIS/ADH/UDH.

 腺病伴UDH。无ADH或DCIS。

试回答丁教授的提问，即UDH与DCIS的鉴别（主要参考陈国璋教授的讲稿）

陈国璋教授把常见病变的鉴别诊断归类于几种模式：
1、小腺体或小管的增生：腺病，硬化性腺病，管状腺病，微腺腺病，小管癌，乳头部腺瘤
2、实性或近似实性的导管内上皮增生：DCIS，UDH，乳头状瘤伴UDH，EDCIS
3、有筛状结构：胶原球（Collagenous spherulosis），UDH，ADH，DCIS，浸润性筛状癌，腺样囊性癌
4、有乳头状结构：乳头状瘤（可合并UDH、ADH、DCIS、EDCIS），多发性乳头状瘤（乳头状瘤病），乳头状DCIS/囊内乳头状癌

其中有关UDH与DCIS的鉴别
UDH：杂乱
腔：分散，大小形状不一，多位于周围（俗称“边窗”）
细胞：胞界通常不清楚，分布不均
核：通常卵圆，有核沟和假包涵体；流水状排列；可以混杂顶浆分泌细胞
IHC：混(CK5+, CAM5.2+)，杂（ER表达不一致）
DCIS：一致
腔：圆而僵硬
细胞：胞界清楚，均匀分布
核：常圆形，深染
Pagetoid扩展，倾向DCIS
IHC：纯（腺型表达：CK5-, CAM5.2+），一致（ER呈均匀一致的强阳性）