Lobular carcinoma in situ of the breast
ICD-10 D05.0 · ICD-11 2E65.0

Classic Lobular Carcinoma In Situ or Atypical Lobular Hyperplasia — Incidental Finding with Radiologic-Pathologic Concordance

When classic LCIS or atypical lobular hyperplasia (ALH) is identified incidentally at biopsy — with confirmed radiologic-pathologic concordance and no additional high-risk lesion present — a specific, evidence-based management pathway applies.

Clinical Scenario

Classic LCIS and ALH are characterised by e-cadherin negative, discohesive cells confined to the terminal ductal lobular unit (TDLU). These findings are typically discovered incidentally during biopsy performed for a separate imaging target. This protocol applies when concordance is confirmed and no co-existing high-risk lesion — such as atypical ductal hyperplasia or non-classic LCIS — is identified.

Management Approach

In this setting, the structured protocol does not involve surgical excision. Instead, it centres on a defined active surveillance strategy — with clinical and imaging follow-up — to monitor for stability over time. The complete follow-up schedule and the full criteria for management are detailed in the structured protocol.

Instant Access to Structured Evidence-Based Regimens

References

  1. Pathologically, ALH and classic LCIS are characterized by e-cadherin negative, discohesive cells in the terminal ductal lobular unit (TDLU), usually identified incidentally at biopsy for another imaging target.
  2. In summary, the decision to recommend excisional biopsy versus active surveillance depends on the variant of LN, imaging findings, and the presence of other high-risk lesions.
  3. Diagnostic imaging at 6, 12, and 24 months to establish stability is recommended based on American College of Radiology guidelines.
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