UnderstandMyScan
Breast imaging illustration
High-Risk Lesions

Atypical Ductal Hyperplasia

ADH is not cancer - but it carries a meaningful upgrade risk and elevates long-term breast cancer risk. Understanding what it means is critical.

Upload Report
Home › Breast Education › Common Findings › Atypical Ductal Hyperplasia (ADH)
Quick Take: Atypical ductal hyperplasia (ADH) is not cancer - it is an abnormal but non-cancerous overgrowth of cells inside the breast ducts. Finding ADH means your future breast cancer risk is elevated, and surgical follow-up is typically recommended. Found in approximately 5–10% of benign breast biopsies.
⚠ High-risk lesion: High-risk lesions are not cancer, but they can be associated with a higher risk of developing cancer or may require surgical removal in some cases.

What Exactly Is ADH?

Hyperplasia means an overgrowth of cells - more cells than normal in a tissue. "Ductal" means this overgrowth is happening inside the milk ducts. "Atypical" means the cells look abnormal under the microscope - they fall somewhere between normal cells and DCIS. They are not cancerous, but they are not entirely normal either.

ADH is a pathology diagnosis - it is found on biopsy, not on imaging. The concern with ADH is twofold:

Two Reasons ADH Requires Follow-Up

1
Upgrade risk

Core needle biopsy samples only a small portion of tissue. ADH cells and DCIS cells look very similar - nearby DCIS may have been missed. The upgrade rate to DCIS or invasive cancer at surgical excision is 10–30%.

2
Future cancer risk marker

Women with ADH have approximately 4–5 times the average lifetime risk of developing breast cancer. This risk affects both breasts and persists long-term.

Key Numbers

10–30%

Upgrade rate to DCIS or invasive cancer at surgical excision

4–5×

Elevated lifetime breast cancer risk compared to average-risk women

Types and Variations

ADH Alone

Upgrade rate to malignancy at excision: 10–30%.

ADH with Other Atypia (ALH, LCIS)

Found alongside lobular neoplasia or other high-risk features - upgrade risk increases further. Surgical excision strongly recommended.

Extensive ADH

Found in multiple cores or involving extensive areas. Higher upgrade risk - surgical excision is the standard recommendation.

What Happens Next

ADH on core biopsy
Surgical excision recommended

Excision is the standard recommendation at most institutions because of the 10–30% upgrade rate.

Excision returns benign (no upgrade)
Excellent outcome - risk reduction strategies discussed

Chemoprevention (tamoxifen or aromatase inhibitors) can reduce future breast cancer risk by approximately 50%.

Excision upgrades to DCIS or cancer
Treatment planning begins

Occurs in 10–30% of cases. Oncology referral and staging initiated.

Enhanced screening
Supplemental MRI may be recommended

Women with ADH and additional risk factors may qualify for annual breast MRI in addition to mammography.

When Should I Be Concerned?

Act promptly if:

Related Topics

→ ALH → LCIS → Radial Scar → Papilloma → Calcifications → BI-RADS Classification

Does your biopsy pathology report mention ADH? This is a high-risk finding that typically requires surgical excision - but it is not a cancer diagnosis. A board-certified radiologist with subspecialty breast imaging experience can walk you through what it means for your specific situation.

Get My Report Explained
This content is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider with any concerns about your breast health.