[199] Type and Grade of Lobular Neoplasia in Breast Core Biopsy: Does It Matter for the Clinician?

A Ghassan, WM Hanna, M Mashhour, S Nofech-Mozes, H Kahn, M Xu, J Zubovits, RS Saad. Sunnybrook Health Sciences Center/University of Toronto, Toronto, ON, Canada

Background: The recent introduction of E-cadherin as a marker for ductal versus lobular origin of breast neoplasia, has led to the recognition of new histologic entities. Previous studies investigating the implication of in situ lobular neoplasia diagnosis on core biopsy are limited by the lack of categorizing the lesions according to their grades and histologic features. We studied the diagnostic implication of different histologic types of in situ lobular neoplasia in breast core biopsy.
Design: We retrieved core biopsies with Atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS) from the hospital archives during 5-years period. In addition, we reviewed core biopsies diagnosed as solid type ductal carcinoma in situ (DCIS) with comedo-type necrosis. Cases were immunostained for E-cadherin and reclassified based on their E-cadherin expression and morphology. Corresponding excision biopsies were examined in all cases.
Results: Out of 126 cases diagnosed as solid type DCIS with comedo necrosis, E-cadherin was negative in 17/126 (13%) and reclassified as LCIS with necrosis (necrotic type). All core biopsies were classified into: 22/48 (46%) cases of ALH/LCIS classic type, 9/48 (19%) cases as LCIS, pleomorphic type and: 17/48 (35%) cases of LCIS with necrosis. On resection, ALH/LCIS group showed benign breast lesion in 8/22 (36%), ALH in 7/22 (32%), LCIS in 2/22 (9%), DCIS/LCIS in 3/22 (14%), and infiltrating lobular carcinoma (ILC)/LCIS in 2/22 (9%). In pleomorphic LCIS group; resection revealed benign breast lesion in 3/9 (33%), LCIS in 2/9 (22%), DCIS/LCIS in 3/9 (33%) and ILC in 1/9 (11%). In LCIS with necrosis group; resection demonstrated pleomorphic ILC in 5/17 (29%), DCIS/LCIS in 4/17 (24%) and LCIS with necrosis in 8/17 (47%).
Conclusions: Our study showed as association between the morphologic features of lobular neoplasia in the core biopsy and histologic findings of lumpectomy. The likelihood of finding more advanced lesions is lower in cores with ALH/LCIS compared with LCIS pleomorphic type and those with necrosis. Also, our study showed that LCIS with necrosis is an under-recognized entity in core biopsy. Although the current recommendation is to treat them similar to DCIS, further investigation of their long term outcome is warranted.
Category: Breast

Monday, March 22, 2010 8:30 AM

Platform Session: Section C, Monday Morning

 

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