Diagnostic disagreements between the original diagnosis of flat epithelial atypia and a low-grade ductal carcinoma in situ and the reviewer´s diagnosis. A: Case originally diagnosed as flat epithelial atypia and considered a columnar cell change without atypia by the reviewer. (Hematoxylin and eosin; x400). B: Case diagnosed by the reviewer as atypical ductal hyperplasia (arrows) adjacent to columnar cell change without atypia (arrowheads) and originally considered by the referral pathologist a low-grade ductal carcinoma in situ. (Hematoxylin and eosin; x100).