Breast: Carcinoma In-Situ

Lobular Carcinoma In-Situ (LCIS)

Basics

  • Definition: Proliferation of Lobule Cells without Basement Membrane Invasion
  • The Lesion Itself Is Not Premalignant (3-5% Risk of Upgrade) Mn
    • Not Technically Cancer
  • Creates a Bilateral Risk for Future Breast Cancer
    • Overall Risk for Future Invasive Cancer: 40%
    • Only 30% of Future Invasive Cancers are Invasive Lobular Carcinoma (ILC)
      • 70% of Future Invasive Cancers are Invasive Ductal Carcinoma (IDC)
  • Only Accounts for 15% of All Breast Cancers

Presentation

  • Most Are Asymptomatic (No Lump or Pain) at Time of Diagnosis
  • Most Often Found Incidentally
  • Most Common in Premenopausal Women

Histologic Classification

  • Classic LCIS: Proliferation of Small Cells with Cytologic Dyshesion & Intracytoplasmic Vacuoles
  • Pleomorphic LCIS: Proliferation of Larger Cells with Marked Nuclear Pleomorphism
    • May Demonstrate Central Necrosis & Calcifications
  • Florid LCIS: Marked Distention of Involved Ducts & Lobules
    • May Demonstrate Central Necrosis & Calcifications

Diagnosis

  • Mammogram: Generally Does Not Cause Calcifications
  • Diagnosis: Core Needle Biopsy (CNB)
  • Cells are Negative for E-Cadherin (Compared to DCIS)
    • Also Seen in ALH & ILC
  • *See Breast: Breast Mass Evaluation

Treatment

  • Primary Treatment: Surgical Excision
  • Margins: No Margin Required
    • May Consider Negative Margins for Pleomorphic LCIS Mn
      • Behaves Similar to DCIS
  • Does Not Require SLNB or XRT

LCIS 1

Pleomorphic LCIS 2

Ductal Carcinoma In-Situ (DCIS)

Basics

  • Definition: Proliferation of Ductal Cells without Basement Membrane Invasion
  • The Lesion Itself Is Premalignant
    • 50% Will Become Invasive
  • Poses an Ipsilateral Risk for Future Breast Cancer

Presentation

  • Most Are Asymptomatic (No Lump or Pain) at Time of Diagnosis
  • Most Often Found Incidentally

Diagnosis

Histologic Classification

  • Comedo Type: Prominent Central Necrosis (Most Aggressive Type)
    • Rapid Growth Past Blood Supply
  • Cribriform Type: Formation of Back-to-Back Glands without Intervening Stroma
  • Micropapillary Type: Intraluminal Projections Perpendicular to the Basement Membrane without Fibrovascular Cares
  • Papillary Type: Intraluminal Projections Perpendicular to the Basement Membrane with Fibrovascular Cares
  • Solid Type: Tumor Cells that Distend & Fill Involved Spaces without Necrosis, Fenestrations or Papillations
  • *Can Also Be Classified Based on Histologic Grade (Low, Intermediate or High)

TNM Staging

  • DCIS is Designated Tis (Stage 0)

Treatment

  • Primary Treatment: Surgical Lumpectomy & Adjuvant Radiation Therapy
    • Margins: 2 mm
      • Reasoning: Spreads Along Basement Membrane So Need Margin
      • If Both DCIS & Invasive Cancer are Present, Goal is “No Ink on Tumor”
        • Behaves More Like Invasive Cancer
    • 10-50% Require Reoperation for Close/Positive Margin
  • Consider Mastectomy for Patient Preference or if Adequate Margins Cannot Be Achieved by Lumpectomy
  • Adjuvant Radiation Reduces Risk of Ipsilateral Recurrence by 50%
    • No Survival Benefit
    • Low-Risk Lesions May Consider Excision Alone without Radiation Therapy
  • Does Not Require SLNB
    • SLNB is Indicated if Preforming a Mastectomy (Unable to do SLNB in the Future)

DCIS 3

DCIS, Comedo Type 4

Mnemonics

LCIS vs DCIS

  • Regarding the Lesion Itself
  • L-Live: LCIS Not Premalignant
  • D-Die: DCIS Premalignant

Pleomorphic LCIS Margins

  • pLEO – L.E.O. (Law Enforcement Officer) is More Strict & Requires Negative Margin

References

  1. Ryan R, Tawfik O, Jensen R, Anant S. Wikimedia Commons. (License: CC BY-4.0)
  2. Wazir U, Wazir A, Wells C, Mokbel K. Pleomorphic lobular carcinomain situ: Current evidence and a systemic review. Oncol Lett. 2016 Dec;12(6):4863-4868. (License: CC BY-NC-ND-4.0)
  3. KGH. Wikimedia Commons. (License: CC BY-SA-3.0)
  4. Bane A. Ductal carcinoma in situ: what the pathologist needs to know and why. Int J Breast Cancer. 2013;2013:914053. (License: CC BY-3.0)