Outline

Intraductal proliferative lesions– Usual ductal hyperplasia (UDH)– Atypical ductal hyperplasia (ADH)– Low grade DCIS– Flat epithelial atypia (FEA)– Clinical significance and management

recommendations

– Not discussing: lobular neoplasia, intermediate and high grade lesions.

Intraductal proliferative lesions

A group of cytologically and architecturally diverse proliferations originating in the TDLU.

Increased risk for subsequent breast ca – but of vastly different magnitudes.

‘risk indicators’ VS ‘precursors’ Different geneticsDifferent morphology: architecture, cytology,

extent.

UDH ADH DCIS INV CA

UDH

CCL/FEA

ADH

LG DCIS

HG DCISDIN terminology?

INV CA

Genetics of intraductal proliferative lesions

H CA

UDH

FEA/CCL

ADH

LG DCIS

HG DCIS

Loss 16q

INV CA

Usual ductal hyperplasia

Also known as epithelial hyperplasia of usual type

Mild, moderate, florid – of no clinical significance*

Architecture: solid, fenestrated, micropapillary (tapered), peripheral slit-like lumens, attenuated bridges

Cytology: variable size and shape, overlapping, ill-defined cell borders, streaming of cells, necrosis is allowed. Occasional mitoses allowed. Compare to normal ducts for reference.