This page gives an introduction to ductal carcinoma in situ - pre-invasive breast cancer.
- By definition, pre-invasive carcinoma
- Confined within ducts and/or lobules
- If genuinely in situ then no risk of metastatic behaviour
- Subclassified into 'ductal' (DCIS) &'lobular'(LCIS)
- Immunostains very helpful in diagnosis e.g CK 5/6, CK14 or P63 to confirm single cell population or lack of invasion - see also Immunohistochemistry and examples on this page of intermediate and high grades below
- DCIS usually managed by excision
- LCIS usually observed
DCIS was very unmcommon before the introduction of population-based breast screening and the overwhlming majority of cases of this condition encountered in developed world clinical practice is screen-detected. The chart below from a recent publication by Elshof et al illustrates this point very well.
Ductal carcinoma in situ (DCIS):
- Confined within ducts
- May occur in isolation - often screen-detected in this situation
- Luminal and periductal calcs common - visible on mammograms
- Nuclear grading most robust and reproducible in terms of predicting prognosis
- Usually admixed with invasive cancer
- When invasive & in situ together nuclear grade of each element often the same
- When present in large ducts beneath the nipple may present as Paget's Disease
- DCIS may extend from the adjacent duct ito lobules - Cancerisation
- Compare the cytology of these cancerisation cells with that of ALH and LCIS
See also additional examples prepared for the Sloane Project website.
DCIS is regarded as a non-obligate precursor of invasive breast cancer; most breast cancers are believed to transition through a DCIS phase, although that phase might be very brief and there are other potential precursors of invasive disease, such as lobular carcinoma in situ, albeit that this is largely regarded as a risk lesion. Of note, the incidence of symptomatic DCIS has remained unchanged in the face of a steeply rising incidence of screen-detected DCIS, suggesting that the latter does not progress to the former. See chart above
An increased body mass index is more strongly associated with invasive carcinoma than DCIS and thus is interpreted as being more powerfully related to disease progression than incidence.
College of American Pathologists Guidelines for grading DCIS:
- Grade 1:
- Monotonous nuclei, 1.5 to 2.0 RBC diameters
- finely dispersed chromatin & only occasional nucleoli
- Grade 2:
- Neither nuclear grade 1 nor nuclear grade 3
- Grade 3:
- Markedly pleomorphic nuclei, usually greater than 2.5 RBC diameters
- coarse chromatin & prominent or multiple nucleoli
Intermediate Grade DCIS
High Grade DCIS
Cancerisation of lobules:
This is the extension of in situ carcinoma (normally DCIS) from ducts into underlying lobules. It can be mistaken for invasive carcinoma in some cases. The use of myoepithelial immunostains such as CK14 can help to deliniate an intact myoepithelium confirming the in-situ status.
See also Image of the Quarter 2013/3 use of pan cytokeratin immunostain to identify small invasive foci accompanying DCIS.
Paget's disease of the nipple
This is uncommon and may be managed by conservation surgery if investigations show that the extent of the disease is limited.
Paget's Disease of the nipple
- Presents as nipple redness/excoriation
- Usually unilateral
- May be confused with eczema
- An indication of high grade DCIS in large ducts beneath
- Paget's cells highlighted with CK7 or HER2 immunostains
- Infiltrates as nests and individual tumour cells (Paget's cells)in the epidermis
- Cytologically similar to Paget's cells
- Positive staining with CK7 and EMA
- Do not stain with Her-2
- Correlate carefully with clinical and mammographic findings before making diagnosis