[226] ER/PR Positive and ER/PR Negative DCIS: Morphologic Characterization in a Cohort of Age-Matched Cases

LP Kunju, CG Kleer. University of Michigan, Ann Arbor, MI

Background: Histologic and molecular data support the concept that DCIS is a heterogeneous disease comprised of different lesions with different biological behavior, in part driven by their hormonal receptor expression. We systematically assessed morphology and associated atypia in cohorts of age-matched ER/PR+ and ER/PR- DCIS.
Design: ER/PR- and age-matched ER/PR + DCIS cases diagnosed between 01/07 and 06/08 were retrieved. We evaluated core and excisional biopsies and recorded the following parameters: nuclear grade, size, architecture, basaloid features, presence of necrosis, calcifications, inflammation, desmoplasia, and associated intra-epithelial lesions including flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH) and lobular carcinoma in-situ (LCIS). We also recorded upgrade to invasive carcinoma on excision.
Results: Twenty ER/PR- and 23 age-matched ER/PR+ DCIS were compared. The mean size of both group was comparable (ER/PR+ DCIS: 1.0 cm, 0.2-3 cm, ER/PR- DCIS: 0.9 cm, 0.2-2.5 cm). The vast majority of ER/PR- DCIS (90%, 18/20) were high nuclear grade vs. 17% (4/23) of ER/PR + tumors. More than one nuclear grade was noted in ER/PR + DCIS only (13%, 3/23). Necrosis and desmoplasia were more common in ER/PR- DCIS (75% vs. 35%, and 75% vs. 26%, respectively). Basaloid histological features were rare, seen in 10% ER/PR- DCIS only. ER/PR+ DCIS had a variety of histological patterns (solid 10/23, cribriform 8/23 or micropapillary 5/23), whereas ER/PR- DCIS was mainly solid and/or apocrine (11/20) or cribriform (5/20). ADH, FEA and/or LCIS was noted in 70% (16/20) of ER/PR+ DCIS, being significantly less common in ER/PR- DCIS (20%, 4/20). FEA was only associated with ER/PR+ DCIS. Core biopsies were performed in 11/23 and 14/20 of ER/PR+ and ER/PR- cases respectively. In 45% (5/11) ER/PR+DCIS, the core biopsy was diagnosed as ADH with or without FEA. Upgrading to invasive carcinoma was only seen in ER/PR- DCIS (10%, 2/20 cases).
Conclusions: ER/PR- DCIS has fairly uniform morphology, and is commonly of high nuclear grade. Basaloid features, though rare, are noted in ER/PR- DCIS only. ER/PR+ DCIS is morphologically more heterogeneous with different architectural patterns, and areas of different nuclear grades. ADH and LCIS are significantly more common in ER/PR+ DCIS. FEA was present in ER/PR+ cases only. The presence of ADH and/or FEA on core biopsies was associated exclusively with ER/PR+ DCIS on excision. When matched for age at diagnosis, the size of ER/PR+ and ER/PR- DCIS is similar, but upgrading to invasive carcinoma is higher in the ER/PR- group.
Category: Breast

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 32, Tuesday Morning