• BACKGROUND
    • The surgical management of lobular in-situ neoplasia (LN) identified by core needle biopsy (CNB) is currently variable. Our institution has routinely excised LN on CNB since 2003, allowing for an unbiased assessment of upgrade rates.
  • METHODS
    • Cases of LN on CNB, including atypical lobular hyperplasia (ALH) and lobular carcinoma-in-situ (LCIS), were identified in our pathology database. CNBs with concurrent pleomorphic LCIS, ductal carcinoma-in-situ (DCIS), and invasive carcinoma were excluded. Imaging indication/modality, biopsy indication, and radiologic concordance were determined. Pathology review included scoring total foci of LN in each CNB. Upgrade rates to invasive carcinoma or DCIS at excision were calculated.
  • RESULTS
    • A total of 106 cases of LN (73 ALH and 33 LCIS) on CNB were identified. Thirty patients had concurrent atypical ductal hyperplasia (ADH) and 76 had LN alone; 93 (88%) of the patients had available surgical follow-up (25 LN + ADH and 68 LN alone). The upgrade rate at excision was 16% (4 of 25) for LN + ADH and 4.4% (3 of 68) for LN alone. Patients with LN alone and discordant imaging, imaging for high-risk indications, or extensive LCIS (>4 foci) accounted for all the upgrades. Normal-risk patients who underwent biopsy to assess calcifications found by routine mammographic screening with LN alone did not result in upgrade.
  • CONCLUSIONS
    • Women with a CNB diagnosis of LN for calcifications found on routine, normal-risk mammographic screening have a negligible risk of upgrade and may not require excisional biopsy. However, excisional biopsy should be offered to women undergoing imaging for other indications or with >4 foci of LN on CNB.