The Significance of Lobular Carcinoma In Situ and Atypical Lobular Hyperplasia of the Breast

Abstract

The significance of lobular neoplasia (LN), lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH)) found at core needle biopsy (CNB) of the breast remains uncertain. There is a consistent risk of underestimating malignancy after the diagnosis of LN on CNB. The aim of this study was to determine if patients with a CNB result of LN need surgical excision. Patients were identified by searching the institutions pathology database for the terms "lobular carcinoma in situ" and "atypical lobular hyperplasia" over 20 years. Excluded from this study were those with core needle biopsy (CNB) results of ductal carcinoma in situ, atypical ductal hyperplasia, radial scar, or papilloma. Upgrade was defined as final surgical pathology of invasive carcinoma and/or ductal carcinoma in situ that was directly correlated to the site of the initial biopsy containing LN. LN was found at CNB in 285 patients, and 71 % (n = 201) had subsequent surgical excisions. All patients with pleomorphic LCIS (pLCIS) underwent surgical excision. Following patients with pLCIS, patients with the diagnosis of LCIS were most likely to undergo surgical excision (80 %). Final pathology of the surgically excised specimens confirmed LN in 72 % (n = 144). Also, 13 % (n = 26) of the operated patients were upgraded to malignancy, including 8 % of ALH and 19 % of LCIS cases. This is the largest series of surgical excisional pathology following LN on CNB ever reported. The likelihood of finding malignancy at surgical excision after CNB showing LN was 13 %. Patients with the diagnosis of LN on CNB should be considered for surgical excision.