Atypical lobular hyperplasia

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Atypical lobular hyperplasia
Diagnosis in short

Atypical lobular hyperplasia. H&E stain. (WC/Nephron)

LM morphologic changes (atypia minimal - usually, borders of cells distinct/visible - dyscohesive, clear cytoplasm (focal), distend duct, eccentric nucleus, usu. round, filled ducts (no luminal spaces - key feature), limited extent (<50% of terminal duct lobular unit is involved)
LM DDx lobular carcinoma in situ, lobular carcinoma
IHC E-cadherin -ve
Site breast

Prognosis benign

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

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


  • May occur with ductal involvement by cells of atypical lobular hyperplasia (abbreviated DIALH).[1]
    • ALH with DIALH has a risk of developing breast cancer that is similar to LCIS.



  1. Morphologic changes - memory device ABCDEF:
    • Atypia minimal - usually.
      • Relatively small ~1-2x size lymphocyte.
    • Borders of cells distinct/visible - dyscohesive.
    • Clear cytoplasm (focal).
      • May have a signet ring cell-like appearance.
    • Distend duct.
    • Eccentric nucleus, usu. round.
    • Filled ducts.
      • No luminal spaces - key feature.
        • Partially filled ducts are not LCIS.
  2. Limited extent: <50% of terminal duct lobular unit (TDLU) is involved.




  • E-cadherin -ve or incomplete membrane staining.

See also


  1. Page, DL.; Dupont, WD.; Rogers, LW. (Feb 1988). "Ductal involvement by cells of atypical lobular hyperplasia in the breast: a long-term follow-up study of cancer risk.". Hum Pathol 19 (2): 201-7. PMID 3343034.