Invasive ductal carcinoma of the breast

Invasive ductal carcinoma of the breast is the most common form of invasive breast cancer. It arises from ductal carcinoma in situ.

Invasive ductal carcinoma of the breast
Diagnosis in short
LM DDx	DCIS, invasive lobular carcinoma of the breast
EM	usu. ER and PR +ve, usu. HER2 -ve, mammoglobin +ve, CK7 +ve, CK20 -ve
Site	breast
Signs	+/-palpable breast mass
Prevalence	common
Prognosis	dependent on stage and grade, good to poor
Clin. DDx	other breast tumours

It is also known as NST (No Specific Type). Generically, it may be referred to as invasive mammary carcinoma.

General

• Most common type of invasive breast cancer.

Gross

• White, firm stellate lesion.

• 
  Ductal carcinoma. (WC)

Microscopic

Features:

• Atypical cells:
  • Usually >2x RBC diameter.
  • Nucleoli common.
  • Forming ducts or sheets.
  • +/-Mitoses.
  • +/-Necrosis.
• Evidence of invasion:
  • Atypical nucleus adjacent to adipocyte - diagnostic.
  • "Infiltrative" pattern:
    • Small glands of variable size within desmoplastic stroma.
    • Glands lined by a single layer of cells.

DDx:

• DCIS.
• Invasive lobular carcinoma.

IHC

Myoepithelial markers - diagnostic for invasion:

• SMMS -ve.
• p63 -ve.

Prognostic markers - may be useful for metastates:

• ER +ve (diffuse).
• PR +ve (diffuse).
• HER2 -ve.

Invasive lobular carcinoma versus invasive ductal carcinoma:

• E-cadherin -ve (includes incomplete membrane staining).

See also

• Invasive breast cancer.
• DCIS.