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.

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.

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.

See also

• Invasive breast cancer.
• DCIS.