33 Special Types of Invasive Breast Carcinoma: Diagnostic Criteria ...

ER Neg.
PR Neg.
HER2 Neg.
CK 5/6 Pos.
“Basal-cell”
Invasive Ductal Carcinoma
of No Special Type
• No internationally accepted definition of basal-like
breast cancer.
• Some use microarray profiling, others IHC markers.
• Proposed IHC panels defining basal-like breast
cancers include:
(1) Lack ER, ER PR, PR & HER2 expression (i.e., (i e any “triple-negative”
“triple negative”
immunophenotype).
(2) Expression of one or more HMW basal CKs (CK5/6,
CK14, CK17).
(3) Lack ER & HER2 in conjunction with CK5/6 and/or EGFR.
(4) Lack ER, PR, & HER2 in conjunction with CK5/6
and/or EGFR.
Basal-like Breast Cancers
• Heterogeneous group, up to 15% of all
breast carcinomas.
• Younger patients, more prevalent in
African-Americans.
• Often present as interval cancers cancers.
• Majority classify as IDC,NST type.
• High histological grade, high mitotic index.
• Often central necrotic or fibrotic zones &
pushing borders.
• Have conspicuous lymphocytic infiltrate.
10/8/2011
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