Atypical lobular hyperplasia

Atypical lobular hyperplasia, abbreviated ALH, a pre-malignant change in the breast characterized cellular proliferation and cellular dyscohesion.

It can be seen as the precursor to lobular carcinoma in situ, the precursor of lobular carcinoma.

General

• May occur with ductal involvement by cells of atypical lobular hyperplasia (abbreviated DIALH).
  • ALH with DIALH has a risk of developing breast cancer that is similar to LCIS.

Microscopic

Features:

• Extent criterium: <50% of terminal duct lobular unit (TDLU) is involved.
• See lobular carcinoma in situ for details.

DDx:

• Lobular carcinoma in situ.
• Lobular carcinoma.

IHC

• E-cadherin -ve or incomplete membrane staining.

See also

• Non-invasive breast carcinoma.