Is excisional biopsy required after a breast core biopsy yields lobular neoplasia?

The management of lobular neoplasia (LN) on percutaneous core breast biopsies remains controversial. Published upgrade rates after surgical excision vary widely. This study aims to determine the frequency of malignancy following excision in patients with LN found on core biopsy.

Our study identified patients from December 2005 through December 2010 with LN as the highest-risk lesion on core biopsy. Patients with flat epithelial atypia on core biopsy were not excluded. Per institutional policy, excision was routinely recommended. An upgrade from the core biopsy of LN was defined as excisional biopsy pathology that revealed ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), or invasive lobular carcinoma (ILC).

Between December 2005 and December 2010, 4472 percutaneous breast biopsies were performed, with 71 patients (1.5%) having LN as the highest-risk lesion on core biopsy. Sixty-seven patients (94%) underwent excision. The upgrade rate on excisional biopsy was 16% (11/67 patients), with the type of malignancy on excisional biopsy pathology as follows: DCIS, 36% (4/11); IDC, 18% (2/11); and ILC, 45% (5/11). All patients with pleomorphic lobular carcinoma in situ on core biopsy who proceeded to excision were upgraded to malignancy. After excluding patients with discordant results, patients with pleomorphic lobular carcinoma in situ, and patients with flat epithelial atypia on core biopsy, the upgrade rate of pure LN on excisional biopsy was 9%.

LN on core biopsy warrants excisional biopsy given the upgrade rate to malignancy.