ihc in the diagnostic of breast disease

8/2/2019 Ihc in the Diagnostic of Breast Disease

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Immunohistochemistry in the

diagnostic evaluation of breast lesions

REVIEW ARTICLE

Appl Immunohistochem Mol Morphol

Volume 19, Number 6, December 2011

David G. Hicks, MD


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Diagnostic IHC in Breast Pathology

1. Predicting benefit from therapeutic agents.

2. Distinguishing true stromal invasion from

mimics (pseudoinvasion)

3. Distinguishing UDH from ADH/DCIS

4. Detect subtle or minimal metastatic disease

in sentinel lymph nodes.

5. Classification andD. Dx for unusual lesions.


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Normal Mammary Ductal/Lobular System


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IHC assessment of stromal invasion:

Antibodies that stain Myoepithelial Cells have

been used to assess stromal invasion in:

1. Small foci of invasion within extensive high

grade DCIS with periductal inflammation.

2. In situ carcinoma involving sclerosingadenosis or other complex sclerosing lesions.


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MEC Markers

++++, strongly positive; +++, positive; ++, moderately positive; +, weakly positive;

+/- equivocal; - negative.

CK indicates cytokeratin; MEC, myoepithelial cell; SMA, smooth muscle actin;

SMM-HC, smooth muscle myosin heavy chain.


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Sclerosing adenosis. A, Low-power view. The lobular configuration of the lesion is

obvious. B, Medium-power view. Note the spindle shape of the proliferating cells in the

center of the lobule and the fibrillary quality of the cytoplasm, indicative of myoepithelial

nature. C, Immunocytochemical stain for actin showing strong immunoreactivity in the

myoepithelial cell component.


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Assessment of Sentinel LN by IHC

SLN biopsy is now the standard of care for axillary

staging in patients with an invasive breast cancer.

The use of cytokeratin stains to identify occult

metastatic disease (isolated tumor cells) in LNs

that are -ve on routine H&E is controversial, and

the clinical significance of such findings is unclear.


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Recent prospective data on clinical outcomes from

randomized trials for recurrence and survival based

on SLN involvement have not shown a clinical

benefit from the IHC detection of occult disease.

However, cytokeratin stains may be helpful in

detecting subtle metastasis for certain primary

tumor as metastatic lobular carcinoma, which can

be difficult to detect by routine H&E in some cases.


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Metastatic lobular carcinoma to an

axillary SLN.

The decision to perform cytokeratinstaining in SLN depends in part on

the morphology of the primary

tumor.

(A) Early LN metastases from lobular

carcinoma can be quite subtle and

difficult to detect in standard H&E.The use of IHC staining for pan-

cytokeratin in this LN (B) highlights

scattered metastatic carcinoma cells

in the subcapsular and medullary

sinuses.


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Not all epithelial cells identified in LNs by H&E or IHC

represent metastatic carcinoma.

Benign glandular inclusions (BGI) in LN

s is an uncommonbut well-documented, they are often located in the

capsule, consist of uniform cells that may contain cilia &

may also be surrounded by myoepithelial cells.

Axillary LNmay also contain benign epithelial cells (oftenfrom an intraductal papilloma) that have been

iatrogenically displaced by needle core biopsy and then

drained to regional LN.


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The failure to carefully evaluate these unusual

cases could lead to improper staging for thepatient and unnecessary therapy.


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Comparison of the morphologic features of the

SLNwith the primary tumor in the breast can

be helpful in establishing the diagnosis of BGI.

Using IHC to demonstrate a myoepithelial layer

surrounding the glandular inclusion may help

confirming the correct diagnosis.


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ihc in the diagnostic of breast disease

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