How is usual ductal hyperplasia (UDH) differentiated from small, peripheral intraductal papilloma (IDP)?

Updated: Dec 25, 2019
  • Author: Joshua I Warrick, MD; Chief Editor: Chandandeep Nagi, MD  more...
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Answer

Answer

UDH can be difficult to distinguish from IDP (S/P ST). UDH is a benign proliferation of a various cell types that takes on a variety of architectures, including micropapillary. It can occasionally be involved by fibrovascular processes, a feature more commonly associated with IDP (S/P ST). Because UDH can have features of IDP (S/P ST), and IDP (S/P ST) can be involved by a UDH-like epithelial proliferation, there is considerable overlap between these lesions, and the authors view them as opposite poles on a histologic spectrum. This spectrum is represented in the images below. In the authors' practice, IDP (S/P ST) is diagnosed only when a prominent, branching fibrovascular core is identified, and the UDH-like proliferation accounts for less than 50% of the lesion.

Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Mild usual ductal hyperplasia (UDH) with a micropapillary pattern (400×).
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. More pronounced usual ductal hyperplasia (UDH) with a micropapillary pattern (200×).
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Usual ductal hyperplasia (UDH) (200×). This example consists of a benign epithelial proliferation that fills a considerable fraction of the duct lumen. The left aspect of the photomicrograph has vaguely papillary features (arrow).
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Usual ductal hyperplasia (UDH) (200×). This example shows a benign epithelial proliferation involving a fibrovascular process (arrow). The lesion consists primarily of proliferative epithelium, and the fibrovascular process shows no convincing branching.
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Usual ductal hyperplasia (UDH) (200×). This example consists of a proliferation of benign epithelium involving a fibrovascular process. The epithelial proliferation comprises the majority of this lesion, and the fibrovascular process shows no branching. Although this was diagnosed as UDH, it should be recognized that this lesion has compelling features of both UDH and small, peripheral intraductal papilloma (IDP) (small/peripheral subtype [S/P ST]), and distinguishing between these two lesions in this case is somewhat artificial.
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Small, peripheral intraductal papilloma (IDP) (small/peripheral subtype [S/P ST]) involved by an abundant usual ductal hyperplasia (UDH)-like epithelial proliferation (arrow) (100×).
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Same small, peripheral intraductal papilloma (IDP) (small/peripheral subtype [S/P ST]) (200×) as in the previous image. In this field, the lesion has the appearance of a common IDP (S/P ST).
Pathology of small, peripheral intraductal papillo Pathology of small, peripheral intraductal papillomas. Same small, peripheral intraductal papilloma (IDP) (small/peripheral subtype [S/P ST]) (200×) as in the previous two images. This field shows the IDP (S/P ST) (black arrow) and the abundant usual ductal hyperplasia (UDH)-like proliferation (blue arrow) that involves it. Although this lesion was diagnosed as IDP (S/P ST), it should be recognized that it has strong features of both UDH and IDP (S/P ST), and strict distinction between these lesions is somewhat artificial in this case.

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