Interpreting the results of a core needle breast biopsy.

Interpreting the results of a core needle breast biopsy.

Assoc. Prof. Yaowanuch Kongdan, M.D.

Interpreting a core needle breast biopsy means reading the pathology report to determine whether the tissue is benign or malignant. Results are often graded B1–B5 (from normal tissue to cancer) and assessed for “concordance” between the pathology and the imaging, which guides whether to monitor, repeat the biopsy, or proceed to surgery. An accurate interpretation is the key to precise, well-planned treatment.

Core needle biopsy is an important method for diagnosing breast cancer. Interpretation and reporting of results are crucial steps in treatment planning. This article describes the interpretation and reporting of breast biopsy results in various cases, including management guidelines and treatment planning in relation to radiological findings and physical examination history. It also covers the concepts of concordance and non-concordance of results, along with the management of different types of tumors diagnosed via core needle biopsy.

Reporting breast biopsy results.

1. B1: Regular meat. (Normal) The tissue sample is normal and requires no further treatment if radiological examinations (such as mammograms or ultrasounds) confirm no abnormalities. Follow-up through routine health checkups is sufficient.

2. B2: Non-cancerous (Benign) , such as fibroadenoma or cyst. If radiological examination confirms no other abnormalities, a routine health checkup is recommended.

3. B3: High-risk lesions such as atypical ductal hyperplasia (ADH) and lobular carcinoma in situ (LCIS). Further biopsy or surgery is recommended to confirm the diagnosis, especially if radiological findings are abnormal.

4. B4: Suspicious of Malignancy. This indicates a high probability that the tissue sample is breast cancer. Further biopsy or surgery is required to confirm the diagnosis before planning treatment.

5. B5: Malignant cancer, such as Invasive Ductal Carcinoma (IDC) and Invasive Lobular Carcinoma (ILC). Before starting treatment, additional special staining tests should be performed to identify the type of cancer, using estrogen and progesterone receptor (ER, PR) staining, HER2-positive cancer, and Ki-67 value. This allows for comprehensive treatment planning in collaboration with a medical team including breast surgeons and oncologists.

   
   

Concordance and Non-concordance

In addition to determining the type of tissue in the biopsy results, it is also necessary to consider the concordance and non-concordance with the results of radiological imaging (mammograms and ultrasounds).

Concordance:

• Explanation: Conformity means that the breast biopsy results match the results of the radiology and physical examination.

• Management: When the biopsy results are consistent with the radiological and physical examination findings, the management approach and treatment plan will proceed based on the biopsy results.

  • Example: If biopsy and radiological examinations reveal a benign tumor, annual follow-up is performed.

Non-concordance:

• Explanation: A mismatch means that the breast biopsy results do not match the results of the radiology or physical examination.

• Management: When biopsy results are inconsistent with radiological and physical examination findings, further investigation is necessary to determine the cause and make a definitive diagnosis.

  • Example: If radiological examination reveals a suspected cancerous mass, but a biopsy finds no cancer cells, is a further biopsy or additional testing using other techniques necessary?

Tissue samples from a core biopsy that need to be surgically removed or treated.

1. Breast cancer (B5): Such as Invasive Ductal Carcinoma (IDC), Invasive Lobular Carcinoma (ILC). Breast cancer treatment should be based on the stage and type of cancer.

2. Suspicious tissue sample (B4): To confirm the diagnosis and prevent future cancer. Further biopsy or surgery may be required.

3. High-risk tissue samples for cancer (B3): Such as Atypical Ductal Hyperplasia (ADH), Lobular Carcinoma In Situ (LCIS), as these have a high risk of developing into future breast cancer. Surgery or further biopsy can aid in diagnosis and prevention.

4. Tissue sample with special features but not cancerous (Benign but with Special Features):

• example:

  • Radial scar: There is a possibility it may be cancerous. Surgery is needed to confirm the diagnosis.

  • Papilloma with atypia: Has a risk of developing into cancer and a possibility of becoming cancerous. Surgery is required to confirm the diagnosis.

  • Phyllodes Tumor: This type of tumor can be both benign and malignant. Surgery is necessary to prevent its growth and spread.

5. Other Lesions:

• Sclerosing adenosis: This can cause diagnostic confusion. Surgery is required for confirmation.

• Fibroepithelial Lesion: such as a large or altered fibroenoma.

• Fat necrosis: Surgery may be necessary if cancer is suspected based on radiographic images.

• Mucinous Lesion: A tumor with specific characteristics may require further examination or surgery.

  
  

summarize

Interpreting core needle biopsy results is a crucial step in breast cancer diagnosis. B1-B5 reporting aids in appropriate treatment management and planning. Considering concordance and non-concordance in the results is essential for effective treatment planning. Patients should be closely monitored and receive the best possible care to maximize their chances of successful treatment and a good quality of life.

Frequently asked questions about interpreting biopsy results (FAQ)

What do biopsy results B1–B5 mean?

The reporting system grades results as B1 (normal), B2 (benign), B3 (uncertain / of risk potential), B4 (suspicious of malignancy) and B5 (malignant). Higher grades indicate a greater likelihood of cancer and usually call for further tests or surgery.

What are concordance and non-concordance, and why do they matter?

Concordance means the pathology result matches what was seen on imaging, which is reassuring. Non-concordance means they don't match — for example, very suspicious imaging but a benign result. In that case the doctor usually recommends a repeat biopsy or surgery to be safe.

My result is B3 (of risk potential) — what happens next?

B3 lesions such as ADH, LCIS or radial scar carry a chance of associated cancer. The doctor often recommends surgical removal to confirm the diagnosis, or close follow-up depending on the individual case.

My result is benign but surgery is recommended — why?

This may be because the result is discordant with the imaging, or because the lesion (e.g. a radial scar) has the potential to harbour cancer. Surgery confirms the result and reduces the risk of missing a hidden malignancy.

What do ER/PR, HER2 and Ki-67 mean on the report?

They describe the tumour's characteristics: ER/PR shows hormone responsiveness, HER2 shows the HER2 receptor status, and Ki-67 indicates how fast the cells divide. These guide the choice of treatment for each patient.

Should I get a second opinion if the result is unclear?

Yes — this is common and reasonable. Having another pathologist or a specialist team review the slides increases confidence in the diagnosis and treatment plan.

Related articles & services

• Core Needle Biopsy of the breast

• Breast biopsy: a complete guide

• Breast diagnosis & screening at Namarak Hospital

Medically reviewed by: Assoc. Prof. Dr. Youwanush Kongdan and the breast-specialist team at Namarak Hospital • Last updated: May 2026

Note: Treatment results depend on the nature of the disease and the individual patient's condition. A guaranteed outcome cannot be guaranteed. Please consult a doctor for a personalized treatment plan.