Surgical outcome of lobular neoplasia diagnosed in core biopsy: Prospective study of 316 cases.
4 Background: Recommendations for management of lobular neoplasia (LN) including lobular carcinoma in situ (LCIS) or atypical lobular hyperplasia (ALH) diagnosed in core biopsy specimens (CB) are controversial. The aim of our prospective study is to identify subset of patients with LN diagnosed in CB who do not require subsequent surgical excision (SE). Methods: All patients with a diagnosis of ALH or LCIS on CB were referred for SE. Cases with coexistent DCIS or invasive breast carcinoma were excluded. Cases with coexistent ductal atypia including FEA or ADH (LN-DA) and LCIS variants including pleomorphic or necrotic LCIS (LN-V) were separated from classic LN (LN-C). Dedicated breast pathologists and radiologists reviewed all cases with careful imaging/pathology (IP) correlation. Results: From June 2008 to December 2013, 13,772 percutaneous breast CB procedures were performed. A total of 370 patients with LN diagnosed on CB were referred to SE. 302 (82%) patients with 316 lesions underwent SE within 2 months after initial diagnosis. Average age was 55.3, 27% had positive family history and 4% had previous breast carcinoma. After patients with synchronous ipsilateral CB showing cancer were excluded (20 patients) from upgrade analysis, the diagnostic groups included 228 LN-C, 15 LN-V and 53 LN-DA. In the LN-C group I/P discordance represented 6/228 cases (2.6%). Upgrade to carcinoma of LN-C varied between discordant (6/6) and concordant cases (8/222=3.6%). In comparison, upgrades were seen in 26.7% LN-V (4/15), and 28.3% LN-DA (15/53). For concordant LN-C, the imaging target was calcifications in 176/222 cases (81%); 7 were associated with upgrade (3.9%). Upgrades were rare for MRI targeted lesions (0/14) and mass lesions (1/32). Overall, upgrades were similar for ALH and LCIS (3.4% vs. 4.5 %). Conclusions: While LN with nonclassic morphology or with associated ductal atypia requires SE, this can be avoided in classic LN diagnosed on CB targeting calcifications when careful imaging/pathology correlation is applied; the likelihood of unsuspected cancer diagnosis is minimal and limited to coincidental cases. Until larger numbers are studied, excising classic LN diagnosed as masses or MRI detected lesions may be prudent.