Flat ductal epithelial atypia

MONDO:0004008

A breast lesion characterized by the presence of dilated terminal ductal lobular units in which the epithelial lining has been replaced by a single layer of mildly atypical cells, or there is atypical, monotonous epithelial hyperplasia of three to five layers. This lesion relates to columnar cell change with atypia and columnar cell hyperplasia with atypia.

Also known as: DIN 1A, FEA, clinging carcinoma, ductal intraepithelial neoplasia, grade 1A, flat ductal epithelial atypia, flat ductal epithelial atypia of the breast, flat epithelial atypia, flat epithelial atypia of the breast

1443 clinical trials for this condition and its sub-types, 3 tagged with Flat ductal epithelial atypia itself.

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↑ Breast intraductal proliferative lesion (154)

Including sub-types (1443) Tagged with Flat ductal epithelial atypia (3)

Trials to join now! 1 Not yet finished but already full! 1 Completed 1

Could a lower tamoxifen dose prevent breast cancer in high-risk women?

Prevention Recruiting now

This study is for premenopausal women at higher-than-average risk for breast cancer. It tests whether a low dose of tamoxifen can safely reduce breast density, which is linked to cancer risk. About 200 women will take tamoxifen, and doctors will adjust the dose if needed to get t…

Phase 2 • Sponsor: National Cancer Institute (NCI) • Aim: Prevention

Last updated Jul 29, 2026 00:00 UTC

Flat ductal epithelial atypia

Where it sits in the disease tree

Could a lower tamoxifen dose prevent breast cancer in high-risk women?