[148] Ductal Carcinoma (DCIS) in Young Women: A Study of the Pathological and Immunohistochemical Features of Pure DCIS in Women <40 Years of Age.

Hillary Elwood, Hind Nassar-Warzecha. The Johns Hopkins Hospital, Baltimore, MD

Background: The features of invasive breast carcinoma in women younger than 40 y of age have been extensively described; the tumors in this age group are more likely to be higher stage and display more aggressive pathological and molecular features than tumors occurring in older women. The characteristics of DCIS lesions in this population (<40 y) have not been well studied.
Design: DCIS cases from women age 18-40 y, diagnosed during the years 2000-2010 were evaluated. We excluded cases with invasion (or microinvasion) in current, previous or subsequent specimens. Pathological features of the DCIS and the adjacent (background) breast tissue, and node status were noted on re-review of the slides. We constructed TMA from paraffin blocks of 20 of these cases. Each case was represented by four 1mm spots (3 DCIS and 1 benign). In total 1 TMA was obtained and labeled with Ki67, CK5/6, HER2, p63 and SMM-HC antibodies. ER and PR status was retrieved from pathology reports; 31 results were available. The cases were subtyped as Luminal A (ER+ and/or PR+; HER2-), Luminal B (ER+ and/or PR+; HER2+), HER2+(ER-, PR-; HER2+), basal-like (BL) (ER-, PR-, HER2-; CK5/6+) or unclassified triple negative (UTN) (ER-, PR-, HER2-,CK5/6-).
Results: Within 10 y period we identified 43 women <40 y of age at the diagnosis of DCIS. DCIS grade was high in 19 (44%), intermediate in 23 (53.5%) and low in 1 (2.5%). Necrosis was present in 35 (81%) cases and calcifications in 29 (67%). Background breast tissue showed non-proliferative changes in 6 (16%), proliferative changes in 29 (74%) cases and ALH in 4 (10%) cases. 1/18 patients with node dissection had micrometastases; in this case, DCIS was high grade with a T size of 5.5 cm.
Three cases were negative for ER and PR. Strong positivity in >90% of the DCIS was seen in 22 (71%) ER and 7(22%) PR stains. HER2 was 3+ in 6 (30%) and 0-1+ in 13 (65%) cases. Ki67 index ranged from 1 to 50% with an average of 10%; 42% of cases had a Ki67 >10%. SMM-HC and p63 labeled myoepithelial cells (MEC) around DCIS ducts in 100% of lesions, with a variable staining among cases (5-100% of the MEC).
DCIS subtypes were: Luminal A in 58.5%, luminal B in 29.5%, HER2+ in 6% and UTN in 6% of the cases.
Conclusions: DCIS in women younger than 40 y appears to have aggressive features including a predominance of intermediate to high grade lesions, necrosis, and high Ki67. Luminal A subtype constitues the majority of the cases however, there is a high proportion of luminal B subtype, which appears to be higher than that described in DCIS in women of all ages (13%).
Category: Breast

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 17, Monday Morning

 

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