Lobular in situ neoplasia

Premalignant disease of the lobules- Lobular in situ neoplasia encompasses two old-term conditions:

• Atypical lobular hyperplasia (ALH)- <50% of the lobule involved
• Lobular carcinoma in situ (LCIS)- >50% of the lobule involved

Clinical features/Epidemiology

• Frequently multifocal and bilateral
• 0.5-4% of all benign biopsies (relatively rare)
  • This decreases further after the menopause (hormone driven neoplasia)
• Normally not palpable/grossly visible
• May calcify and present at mammography as an incidentle finding / screening

Pathology

• Intralobular proliferation with characteristic features:
  • Small intermediate sized nuclei
  • Solid proliferation
  • Intracytoplasmic lumens/vacuoles
  • Oestrogen receptor (ER) positive / E-cad negative
• NB IMPORTANT:
  • 20% of cases with lobular neoplasia at core biopsy actually have a higher grade lesion on open excisional biopsy (i.e. definitive cancer)
    • 8-fold increase in risk of carcinoma if LISN present (i.e. a genuine precursor to cancer)
    • This increase is time dependent too:
      • ALH- 10% 5-year risk
      • ALH and a FHx- >20% 5 year risk
      • LCIS +/- FHx- 20% 5 year risk

Management

• If diagnosed on core biopsy- excise and follow up
• If diagnosed on excision biopsy- follow up
• Tamoxifen is usually used in these patients too

Advertisement