Usual ductal hyperplasia(UDH) versus Atypical Ductal Hyperplasia/DCIS

The useful immunohistochemical marker in this setting would be CK5/6. If there is heterogenous staining in the intraductal proliferation, this would favor UDH rather than ADH/DCIS.

Atypical Ductal Hyperplasia verus DCIS

The criteria to be fulfilled for a lesion as ADH

-Size criterion: less than 3mm

-Nuclear grade: low grade

If the lesion shows high nuclear grade, it is high grade DCIS, no matter how small it is.

If the lesion shows low nuclear grade, it is low grade DCIS, if it is more than 3mm in size.