Histology of DCIS
Ductal carcinoma in situ (DCIS) is one of several epithelial proliferative breast diseases which include: epithelial hyperplasia, atypical ductal hyperplasia (ADH), DCIS and invasive ductal carcinoma (IDC). Ductal epithelial hyperplasia without atypia confers only a slight risk of progression to IDC, about 1.5-2x greater risk then normal ductal epithelium. Atypical ductal hyperplasia confers a moderate risk of progression to IDC, about 4-5 times greater than normal ductal epithelium. DCIS (low grade) increases the risk of progression to IDC about 8-10 times normal. A very high risk, ≈ 50% of recurrence or IDC is associated with high grade DCIS.
Over time several systems have been created to differentiate DCIS from hyperplasia and help categorize the risk posed by a particular DCIS lesion. Early classifications based on a combination of architectural growth pattern and cytological features, suffered from poor reproducibility. In 1997 the Consensus Conference on the Classification of Ductal Carcinoma In Situ recommended that the following feature should be decribed when confirming the presence of DCIS: 1. Nuclear grade 2. Necrosis 3. Polarization 4. Architectural pattern(s).•
Growth patterns and architectural classification was the earliest attempts to classify DCIS lesions. The following architectural patterns are listed from least aggressive to most aggressive forms:
A. Papillary pattern: Characterized by fern-like processes within the duct. Cells are arranged around fibrovascular cores
B. Micropapillary pattern: Characterized by small tufts of cells within the duct. The tufts lack fibrovacular cores present in papillary forms. Cells are small to medium in size, and the nuclei show diffuse hyperchromasia; mitoses are infrequent.
C. Cribriform pattern: Characterized by fenestrations between cells. Cells are smaller and more uniform compared to comedo pattern. This pattern may also be present in comedo DCIS.
D. Solid pattern: Characterized by a lack of significant necrosis, fenestrations, or papillae. Cells may be large medium or small, they fill and distend the duct.
E. Comedo pattern: Characterized by prominent central necrosis. The necrotic material often becomes calcified, enhancing detection on mammogram. Calcified "casts" may be linear, branching or granular. Cells are large with nuclear pleomorphism. Mitotic activity is often elevated.
F. Invasive ductal carcinoma: Characterized by erosion through the basemant membrane and migration of abnormal cells into the surrounding tissue.
Architecture and growth patterns are still included in the pathology report but their clinical relevance is suspect for many reasons:
Nuclear grading has greater predictive value then architectural pattern alone.•
- Low grade (Grade I) - monomorphic nuclei (well differentiated)
- nucleus size ≈ 1.5X to 2.0X RBC diameter or = to a normal duct epithelial cell nucleus
- finely dispersed chromatin
- occasional nucleoli
- occasional mitoses
- nuclei polarized toward the luminal space.
- often estrogen receptor (ER) and progesterone receptor (PR) rich
- intermediated nuclear shape
- intermediate size
- intermediate chromatin dispersal
- intermediate nucleoli
- intermediate mitoses
- intermediate polarization of nuclei
- nucleus size >2.5X RBC or a normal duct epithelial cell nucleus
- vesicular and irregular chromatin distribution
- nucleoli are prominent and often multiple
- mitoses may be frequent
- nuclei usually not polarized toward the luminal space
- associated with increased risk of local recurrence
- often estrogen receptor (ER) and progesterone receptor (PR) poor
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