When your breast was biopsied, the samples taken were studied under the microscope by a specialized doctor with many years of training called a pathologist. The pathology report tells your treating doctor the diagnosis in each of the samples to help manage your care. This FAQsheet is designed to help you understand the medical language used in the pathology report.

1. What is "carcinoma" or "adenocarcinoma"?

Breast carcinoma or adenocarcinoma is synonymous with breast cancer which is malignant, although can be curable when caught early.

2. What is "infiltrating" or "invasive"?

These words mean the same. The normal breast is made of ducts that end in a group of blind-ending sacs (lobules). Carcinomas start out in the ducts and lobules and when the break out of these structures and are no longer confined to the breast ducts or lobules, they are considered invasive or infiltrating carcinoma.

3. What does it mean if my carcinoma is called "ductal" or "lobular" or "carcinoma with duct and lobular features"?

Breast carcinomas have different appearances under the microscope. The two major patterns seen in breast carcinoma are ductal carcinoma or lobular carcinoma. In some cases, the tumor can have features of both and are called mixed ductal and lobular carcinoma. In general, there is not a significant different prognosis between invasive lobular and invasive ductal adenocarcinoma of the breast.

4. What does it mean if my report mentions E-cadherin.

E-cadherin is a test that the pathologist uses to help determine if the tumor is ductal or lobular. If your report does not mention E-cadherin, it means that this test was not necessary to make the distinction.

5. What does it mean if my carcinoma is "well-differentiated", "moderately-differentiated", or "poorly differentiated"?

These terms are used to indicate how aggressive your carcinoma is likely to be. It is made by a pathologist looking at the cancer under the microscope. Well-differentiated carcinomas tend to be more slowly growing with a better prognosis. Poorly-differentiated carcinomas are the most aggressive tumors with a worse prognosis with moderately-differentiated carcinomas having an intermediate prognosis.

6. What is "histologic grade" or "Nottingham grade"?

These grades are similar to what is described above under "differentiation". Numbers are assigned to different features seen under the microscope and added up to make up the grade. The added numbers range from 3 to 9. 3-5 equal to grade 1 (well-differentiated); 6-7 equal to grade 2 (moderately differentiated); and 8-9 equal to grade 3 (poorly differentiated). In some reports they also may be described as Elston grade.

7. What does it mean if ki67 is mentioned in my report.

Ki67 is measurement of the proliferation rate of the cancer cells. The pathologist determines the proliferative rate of the cancer cells under the microscope. This a measure of how rapidly the cancer is dividing, another indication of prognosis.

8. What does it mean if my carcinoma has "tubular", "mucinous", "cribriform", or "micropapillary" features?

These are different types of ductal carcinoma. Tubular, mucinous, and cribriform carcinomas are types of well-differentiated cancers with typically a better prognosis. Micropapillary carcinomas are associated with a worse prognosis. However, a definite diagnosis of these types of cancer cannot be established on needle biopsy, since some tumors may have mixed features. Only if most of the tumor shows these features, which can only be done once the entire tumor is removed on lumpectomy or mastectomy, can these types of cancer be definitively diagnosed.

9. What is "vascular" or "lymphovascular invasion"? What if my report mentions D2-40 (podoplanin) or CD34?

Tumors cells can break into small vessels seen under the microscope which is called "vascular" or "lymphovascular invasion". The presence of tumor in vessels is associated with an increased risk that the tumor has spread outside the breast, although this does not always occur. D2-40 and CD34 are special tests that the pathologist may do to help identify vascular invasion. These tests are not necessary in every case. If your report does not mention vascular or lymphovascular invasion, it means it is not present. Even with vascular invasion your cancer could still be very curable depending on other factors. How this finding will affect your specific treatment is best discussed with your treating doctor.

10. What is the significance of the reported size of the tumor?

The pathologist typically will measure the greatest dimension of the tumor as seen under the microscope or by gross (naked eye) examination (if visible). Not all cancers on needle biopsy are given a measurement, as the more accurate measurement will be done on the subsequent excision (lumpectomy or mastectomy).

11. What is the significance of the stage of the tumor?

The stage of the tumor is a measurement of its extent both in the breast and whether there is any spread beyond the breast. A stage is typically not given for a needle biopsy specimen as the pathologist does not have the entire tumor to evaluate. For lumpectomy specimens, a stage is usually reported that takes into consideration the size of the tumor, which is indicated by "pT" followed by numbers and letters to indicate its size. The larger the number, the larger the tumor size. "pN" followed by numbers and letters indicate if and the extent of spread to any lymph nodes (see below) that may have been removed with the specimen. "pMx" means that the pathologist cannot determine whether there is spread to distant sites (ie. lung, liver, bone) because this must be determined by radiographic studies. How the stage of your tumor will affect your therapy is best discussed with your treating physician.

12. What if my report mentions "sentinel lymph node"?

This FAQ concerns itself with the explanation of pathologic terms in breast biopsies. Occasionally, breast biopsies done for carcinoma are accompanied by a lymph node. Information regarding breast cancer lymph nodes can be found at the following websites:


13. What does it mean if my report mentions special studies such as high molecular weight cytokeratin (HMWCK), ck903, ck5/6, p63, muscle specific actin, smooth muscle myosin heavy chain, calponin, or keratin?

These are special tests that the pathologist sometimes uses to help make the diagnosis of invasive breast cancer or to identify cancer in lymph nodes. Not all cases need these tests. Whether your report does or does not mention these tests has no bearing on the accuracy of your diagnosis.

14. What does it mean if my report also says any of the following terms: "usual duct hyperplasia", "adenosis", "sclerosing adenosis", "radial scar", "complex sclerosing lesion", "papillomatosis", "papilloma", "apocrine metaplasia", "cysts", "columnar cell change", "collagenous spherulosis", "duct ectasia", "fibrocystic changes", "flat epithelial atypia", or "columnar cell change with prominent apical snouts and secretions (CAPSS)"?

All of these terms are non-cancerous things that the pathologist sees under the microscope and are of no importance when seen on a biopsy where there is cancer.

15. What does it mean if my report mentions "microcalcifications" or "calcifications"?

Microcalcifications or calcifications are minerals that are found in the both noncancerous and cancerous breast lesions and can be seen both on mammograms and under the microscope. They are reported by the pathologist to show that the abnormal area seen in the mammogram was successfully sampled by the biopsy. By themselves, they do not have any significance.

16. What does it mean if in addition to cancer my report also says "atypical duct hyperplasia (ADH)" or "atypical lobular hyperplasia (ALH)" or "ductal carcinoma in-situ (DCIS)" or "intraductal carcinoma", or "lobular carcinoma in-situ (LCIS)" or "in-situ lobular carcinoma"?

All of these terms are pre-cancerous things that the pathologist sees under the microscope. These typically are of no importance when seen on needle biopsy if there is invasive cancer elsewhere on the sampling. If they are seen on an excision (lumpectomy) where there is cancer, they may be important if present at or near a margin (see FAQ relating to margins below).

17. What does it mean if my report mentions "estrogen receptor (ER)" or "progesterone receptor (PR)"?

ER and PR are special tests that the pathologist does that are important to predict response of the cancer to certain types of therapy. Women have circulating estrogen and progesterone in their blood, and some cancers might grow more readily if the circulating estrogen and progesterone attach to these receptors. By determining if these receptors are present in the cancer, your treating physician may explore with you possibility of drugs that block these receptors. Results for ER and PR are reported separately and can be reported in different ways: 1) negative, weakly positive, positive; 2) percent positive; 3) percent positive and whether the staining is weak, moderate, or strong. How the results of your tests will affect your therapy is best discussed with your treating physician.

18. What if my report mentions HER2/neu?

Some breast cancers (about 15 – 20%) have on the surface of the cancer cells a protein called HER2/neu. HER2 is a special test done by pathologists that is predictive of both the prognosis and the response to certain types of therapy. HER2 is usually first tested in breast cancer using a technique called immunohistochemistry (IHC) and typically reported as 0 (negative), 1+ (weakly positive), 2+ (moderately positive), and 3+ (strongly and diffusely positive). In certain cases the results with IHC are considered equivocal and a more precise, yet also more complicated and expensive, test is performed. This test is called fluorescence in situ hybridization (FISH) or in situ hybridization (ISH). If the protein is present, your treating physician may choose a different set of drugs to treat the breast cancer. How the results of your tests will affect your therapy is best discussed with your treating physician.

19. What if my report mentions "margins" or "ink"?

When an excisional biopsy (lumpectomy) is performed, the pathologist coats the outer aspect of the specimen with ink, sometimes different colored ink. If carcinoma extends to the ink, it indicates that it may not have been completely removed. The management of "invasive carcinoma", "intraductal carcinoma" (pre-cancer), "in-situ lobular carcinoma" (pre-cancer), "atypical duct hyperplasia"(early pre-cancer), or "atypical lobular hyperplasia (early pre-cancer)" at a margin is best discussed with your treating physician.