- DCIS is a proliferation of malignant epithelial cells:
- Confined to the mammary ducts and without evidence of invasion through the basement membrane
- They arise from ductal epithelium:
- In the region of the terminal ductal–lobular unit
- DCIS had previously been considered one stage in the continuum of histologic progression from ADH to invasive carcinoma:
- It is now understood that DCIS comprises a heterogeneous group of lesions:
- With variable histologic architecture, molecular and cellular characteristics, and clinical behavior (Figure)
- It is now understood that DCIS comprises a heterogeneous group of lesions:
- Malignant cells proliferate until the ducts is obliterated:
- There may be associated breakdown of the myoepithelial cell layer of the basement membrane surrounding the ductal lumen
- DCIS has also been linked with changes in the surrounding stroma:
- Resulting in fibroblast proliferation, lymphocyte infiltration, and angiogenesis
- Thus, although the process is poorly understood:
- Most, but not all, invasive ductal carcinomas are believed to arise from DCIS:
- Therefore, DCIS is considered a nonobligate precursor of invasive breast carcinoma with a variable risk of progression:
- Depending on a combination of pathologic factors:
- These factors include:
- Growth pattern, histologic grade, presence or absence of necrosis, size of the lesion, margin status, and expression of tumor biomarkers (estrogen and progesterone receptors)
- These factors include:
- Depending on a combination of pathologic factors:
- Therefore, DCIS is considered a nonobligate precursor of invasive breast carcinoma with a variable risk of progression:
- Most, but not all, invasive ductal carcinomas are believed to arise from DCIS:
- Common growth patterns of DCIS include:
- Solid, cribriform, micropapillary, and papillary
- Cribriform, solid, and micropapillary:
- Are the more common subtypes:
- Two or more patterns coexist in up to 50% of cases
- Are the more common subtypes:
- Nuclear grading is based on:
- The size, texture, and nucleoli
- Similar to invasive carcinoma, three grades are recognized for DCIS:
- Low-grade lesions:
- Are characterized by a proliferation of monotonous cells with well-defined cell borders:
- Uniformity of nuclear features is the key feature
- Are characterized by a proliferation of monotonous cells with well-defined cell borders:
- Intermediate grade lesions:
- Have nuclear features are in between low and high grade:
- Central (comedo) necrosis is most frequently associated with high-grade lesions:
- Less frequently found in intermediate lesions and very rarely present in low-grade lesions
- Central (comedo) necrosis is most frequently associated with high-grade lesions:
- Have nuclear features are in between low and high grade:
- High-grade DCIS is composed of pleomorphic cells with variable nuclear size and shape:
- Mitoses are frequent in individual cells and comedonecrosis is common
- Both the World Health Organization (WHO) and the College of American Pathologists (CAP):
- Recommend that architectural and nuclear features and the presence of comedonecrosis should be evaluated independently of one another and all of these features should be included in pathology reports
- Low-grade lesions:
- Since DCIS only rarely forms a grossly visible mass:
- Measurement of lesion size is typically done by microscopic evaluation:
- The pathologist must be able to reconstruct the specimen to estimate size of the lesion:
- This is a difficult task and requires that the histologic sections be submitted in orderly fashion to permit such reconstruction:
- Even so, it is sometimes difficult to assess lesion size when small foci of DCIS are scattered throughout the resected specimen:
- As most recurrences of DCIS probably represent persistence of DCIS following incomplete removal:
- The evaluation of margins is not trivial
- As most recurrences of DCIS probably represent persistence of DCIS following incomplete removal:
- Even so, it is sometimes difficult to assess lesion size when small foci of DCIS are scattered throughout the resected specimen:
- Routine specimen mammography and careful sectioning of the specimen are required
- The most common approach involves the application of different colored inks to the surfaces of a specimen that has been oriented by the surgeon
- The specimen is then submitted for histologic examination in serial sections and the shortest distance between DCIS and the inked margin is reported as the margin width
- This is a difficult task and requires that the histologic sections be submitted in orderly fashion to permit such reconstruction:
- The pathologist must be able to reconstruct the specimen to estimate size of the lesion:
- Measurement of lesion size is typically done by microscopic evaluation:
- In a joint consensus statement, the Society of Surgical Oncology (SSO), the American Society for Radiation Oncology (ASTRO), and the American Society of Clinical Oncology (ASCO):
- Recommended the margin width for breast-conserving surgery for DCIS to be 2 mm based on data from patients treated with adjuvant whole-breast radiation:
- A 2-mm margin was determined after comparison to narrower margin widths demonstrated a significant decrease in in-breast recurrence:
- However, the panel recommended exercising clinical judgment based on other clinical and imaging factors when determining the need for reoperation for re-excision for patients with margins < 2 mm
- A 2-mm margin was determined after comparison to narrower margin widths demonstrated a significant decrease in in-breast recurrence:
- Recommended the margin width for breast-conserving surgery for DCIS to be 2 mm based on data from patients treated with adjuvant whole-breast radiation:
- In addition to tumor factors:
- Stromal features have also been found to be prognostic in DCIS lesions:
- The presence of periductal fibrosis has been associated with increased likelihood of recurrence
- Stromal tumor-infiltrating lymphocytes (TILs):
- Have been found to be associated with:
- Younger age, larger tumor size, higher nuclear grade, comedonecrosis, and estrogen receptor negative status
- Have been found to be associated with:
- Stromal features have also been found to be prognostic in DCIS lesions:
- Given all of these considerations, the pathology report in cases of DCIS should include a large amount of data:
- The College of American Pathologists (CAP) has recommended use of a template form to ensure that all histopathologic data are reported:
- Such a form would typically include histologic pattern, nuclear grade, presence of necrosis, distance to margin, size, presence of calcifications, and status of estrogen and progesterone receptor expression
- The College of American Pathologists (CAP) has recommended use of a template form to ensure that all histopathologic data are reported:
Rodrigo Arrangoiz MS, MD, FACS, FSSO 