The short answer
Atypical ductal hyperplasia, or ADH, is a benign (not cancer) breast condition. NCI says there are more cells than normal in the lining of the breast ducts, and they look abnormal. Having ADH raises the risk of breast cancer. A related finding, atypical lobular hyperplasia (ALH), is in the lobules. This page explains both and what to ask your care team.
NCI says ADH is benign, meaning not cancer.
In ADH, there are more cells than normal in the lining of breast ducts, and they look abnormal under a microscope.
NCI says having ADH increases the risk of breast cancer.
Atypical lobular hyperplasia (ALH) is a similar benign finding in the lobules that NCI says also raises risk.
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This page is for anyone whose breast biopsy report says "atypical ductal hyperplasia" or "ADH." It explains the term and what to ask your care team.
What ADH means
NCI defines atypical ductal hyperplasia as "a benign (not cancer) condition in which there are more cells than normal in the lining of breast ducts and the cells look abnormal under a microscope."
Break the name down:
- Atypical: the cells look abnormal.
- Ductal: it is in the ducts, the tubes that carry milk.
- Hyperplasia: there are more cells than normal.
Why it matters
NCI says: "Having atypical ductal hyperplasia increases the risk of breast cancer." ADH is not cancer. But your care team may talk with you about next steps, follow-up, or screening.
A related term: atypical lobular hyperplasia
Some reports say atypical lobular hyperplasia, or ALH. NCI describes it the same way, except the extra abnormal-looking cells are in the lobules, the milk-making glands. NCI says ALH also increases the risk of breast cancer.
Ask these before you leave
- Is ADH the only finding on my report?
- Do you recommend any more tissue be removed or checked?
- What follow-up or screening fits my risk?
Related pages
See What Does Hyperplasia Mean on a Pathology Report?, What Does 'Atypia' Mean?, and What Does LCIS Mean?.
Sources
Common questions
Is atypical ductal hyperplasia cancer?
No. NCI calls it a benign (not cancer) condition. It does raise the risk of breast cancer.
What is the difference between ADH and ALH?
Location. ADH is in the lining of the breast ducts. ALH is in the lobules. NCI says both raise breast cancer risk.
What happens after an ADH result?
That depends on your whole report and history. Ask your care team what they recommend and why.
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Sources last checked: 2026-10-02 what this meansLast updated: 2026-09-27Next planned review: 2027-09-27
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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