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Pathology FAQ: Breast Cancer In-Situ
UNDERSTANDING YOUR PATHOLOGY REPORT: A FAQ SHEET
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 FAQ sheet is designed to help you understand the medical language used in the pathology report.
1. What is “in-situ carcinoma”?
In-situ carcinoma is a pre-cancer. The normal breast is made of ducts that end in a group of blind-ending sacs (lobules). Carcinomas originate in the ducts and lobules and when they have not broken out of these structures and are still confined to the breast ducts or lobules, they are considered ductal or lobular “in-situ carcinoma”, respectively.. Once in-situ carcinoma has grown and broken out of the ducts or lobules it is referred to as “invasive” or “infiltrating” carcinoma, which means that the tumor cells now have the potential to spread (metastasize) to other parts of your body.
2. What does it mean if my in-situ carcinoma is called “ductal carcinoma in-situ”, “intraductal carcinoma”, “lobular carcinoma in-situ” or “in-situ carcinoma with duct and lobular features”?
In-situ carcinomas of the breast have a variety of appearances under the microscope, the two major types being ductal carcinoma in-situ (DCIS) or lobular carcinoma in-situ (LCIS). “Intraductal carcinoma” and “ductal carcinoma in-situ” are synonymous terms. Ductal carcinoma in situ is considered a direct precursor of invasive breast cancer. It is usually treated by excision plus radiation or mastectomy. Lobular carcinoma in situ is considered more of a marker of increased cancer risk. A limited excision is usually recommended when it is diagnosed on a needle biopsy. Excision to clear margins is not required for LCIS, the excision is not followed by radiation and it is not necessary to do a mastectomy to treat it.
3. What does it mean if my report mentions E-cadherin?
E-cadherin is a test that the pathologist uses to help determine if cancer cells are ductal or lobular. If your report does not mention E-cadherin, it means that this test was not necessary to make the distinction.
4. What does it mean if my ductal carcinoma in-situ is described as being “cribriform”, micropapillary”, “apocrine”, “comedo”, “with comedonecrosis”, “papillary”, or “solid”?
These are different microscopic appearances of ductal carcinoma in-situ that may have little importance for determining the best treatment.
5. What does it mean if my ductal carcinoma in-situ is described as being “low grade”, “intermediate grade”, or “high grade”; or “nuclear grade 1”, “nuclear grade 2”, or “nuclear grade 3”; or “low mitotic rate”, “intermediate mitotic rate”, or “high mitotic rate”?
These are all different ways of describing the microsopic appearance of ductal carcinoma in-situ (DCIS) cells. High grade DCIS has a slightly greater recurrence risk than low or intermediate grade DCIS. .
6. What is the significance of the reported size of the ductal carcinoma in-situ (DCIS)?
The extent of DCIS can be difficult to measure under the microscope. The pathologist may estimate the size of the DCIS based on the gross (naked eye) examination or by noting the number of microscopic slides that contain DCIS as compared to the total number of slides examined.
7. What is the significance of ductal carcinoma in-situ (DCIS) in terms of prognosis and treatment?
DCIS is a pre-cancer but its natural history is not well understood. Treatment is aimed at reducing the future risk of invasive breast cancer. Treatment options usually include lumpectomyt alone, lumpectomy with radiation, or mastectomy. Anti-hormonal therapy is discussed for DCIS that has been treated by lumpectomy and is positive for estrogen receptor.
8. 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 ductal carcinoma in-situ. 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.
9. What does it mean if my report on ductal carcinoma in-situ (DCIS) mentions “estrogen receptor (ER)”?
ER is a special test that the pathologist does on the excised DCIS. The result is used to determine whether anti-hormonal therapy will be recommended. The ER result 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.
10. What if my report on ductal carcinoma in-situ (DCIS) mentions “margins” or “ink”?
When partial mastectomy (lumpectomy)is performed for DCIS, the pathologist coats the outer aspect of the specimen with ink, sometimes different colored ink. If DCIS extends to the ink, it indicates that it may not have been completely removed (i.e.it is at the surgical “margin”). However, the surgeon may have removed additional tissue at the time of the excisional biopsy to guard against this possibility. If the DCIS has not been completely removed, additional treatment (surgery, radiation, or hormone therapy, or a combination of these) is typically used to get rid of the residual DCIS. Management of DCIS at a surgical margin is best discussed with your treating physician.
11. What is the significance of lobular carcinoma in-situ (LCIS) in terms of prognosis and treatment?
The presence of LCIS increases the risk of subsequently developing carcinoma in both breasts. Typically, LCIS found on excision is managed with observation, and in some cases, with hormone therapy. The appropriate treatment of LCIS found on needle biopsy is an area of uncertainty and is best discussed with your treating physician.
12. What does it mean if my report mentions “lobular neoplasia”?
Lobular neoplasia is a generic term for abnormal growth of the milk gland cells. Many prefer this term to lobular carcinoma in situ because it does not contain the word “carcinoma.” Lobular neoplasia is a marker for increased breast cancer risk.
13. What if my lobular carcinoma in-situ (LCIS) is described as “pleomorphic” or “with necrosis”?
These types of LCIS, when compared to LCIS without these features, may be more aggressive and associated with an increased risk of carcinoma. “Necrosis” means that some of the LCIS cells are dead. “Pleomorphic” means that the LCIS cells have bizarre shapes and sizes under the microscope. Pleomorpic LCIS is usually treated the same as DCIS.
14. What if my report on lobular carcinoma in-situ (LCIS) mentions “margins” or “ink”?
When an excisional biopsy (lumpectomy) of LCIS is performed, the pathologist coats the outer aspect of the specimen with ink, sometimes different colored ink. If LCIS extends to the ink, it indicates that it may not have been completely removed (i.e.it is at the surgical “margin”). However, the surgeon may have removed additional tissue at the time of surgery to guard against this possibility. Even if LCIS has not been completely removed,, it is typically not treated with further excision. However, in some cases, such as pleomorphic LCIS, LCIS with necrosis, or LCIS that make a mass that is palpable or seen on mammography, it may be treated with additional excision. The management of LCIS at a margin is best discussed with your treating physician.
15. What does it mean if my report also mentions “atypical ductal hyperplasia (ADH)” or “atypical lobular hyperplasia (ALH)”?
These are precursors to ductal carcinoma in-situ and lobular carcinoma in-situ, respectively. The significance of these changes often depends on the associated lesions and is best discussed with your treating physician.
16. 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 changes that the pathologist sees under the microscope and are of no importance when seen on a biopsy where there is in-situ cancer.
17. What does it mean if my report mentions “microcalcifications” or “calcifications”?
“Microcalcifications” or “calcifications” are minerals that are found in 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 with calcifications seen on the mammogram was successfully sampled by the biopsy. Without accompanying worrisome changes in the breast ducts or lobules, “microcalcifications” or “calcifications” alone have no significance.
Navigate our Pathology FAQs and Images
- Benign Breast FAQ
- Benign Diseases - Atlas of Images
- Atypical Hyperplasia
- Breast Cancer In-Situ
- Breast Cancer
- Malignant Tumors - Atlas of Images
- Ask an Expert - Understanding Pathology Results
Authors: Jeanne Simpson (Vanderbilt Medical Center), Stuart Schnitt (Beth Israel Deaconess Medical Center), Jonathan I. Epstein (Johns Hopkins Medical Institutions)