Pathologic upgrade rates on subsequent excision when lobular carcinoma in situ is the primary diagnosis in the needle core biopsy with special attention to the radiographic target.

CONTEXT: Lobular carcinoma in situ (LCIS) as the primary pathologic diagnosis in a needle core biopsy is an infrequent finding, and the management of patients in this setting is controversial.
OBJECTIVE: To determine the rate of pathologic upgrade (defined as the presence of a clinically more-significant lesion in the subsequent excision) in patients with a primary pathologic diagnosis of LCIS in the needle core biopsy.
DESIGN: Patients with a primary diagnosis of LCIS in a needle core biopsy who underwent subsequent excision were identified. Core biopsies containing a concurrent high-risk lesion and cases with radiologic-pathologic discordance were excluded. The presence of selected microscopic features in the needle core biopsy was correlated with pathologic upgrade. Microscopic findings were correlated with the radiographic target in the needle core biopsy.
RESULTS: Sixty-one women with primary LCIS in their needle core biopsy showed a 10% pathologic upgrade rate. The percentage of cores involved by LCIS was significantly associated with pathologic upgrade (P= .04), whereas the remaining measured parameters were not. When LCIS represented the radiographic target, the pathologic upgrade rate was 18%, whereas when it was an incidental finding, the pathologic upgrade rate was 4%.
CONCLUSIONS: It may be reasonable for patients with primary, yet incidental, LCIS on needle core biopsy to be managed in a nonsurgical fashion. Larger studies are needed to confirm our findings.