[172] Ductal Carcinoma In Situ in Women under Age of 35

J Gao, ME Sullivan, SA Khan, B Susnik. Northwestern University Feinberg School of Medicine, Chicago, IL

Background: DCIS is rare under age of 35 years. The evolution of invasive carcinoma (IC) in this age group may be different from that in older women and is not well understood. The high frequency of triple negative/basal vs. luminal phenotype in young may indicate differences or even absence of traditional precursor lesions in this population. We retrospectively reviewed the clinical, morphologic and phenotypic characteristics of DCIS in women <35 years old.
Design: We identified 66 women <35 years presenting with breast carcinoma diagnosis from 2005- 2007. All cases with DCIS (with or without invasive component) were included. We reviewed the morphology, existing clinical data, and the immunohistochemistry (IHC) profile including ER, PR, HER-2, p53, Ki67, and CK5/6.
Results: Study cases included 19 invasive carcinoma (IC), 38 DCIS with IC (DCIS+I), and 9 with pure DCIS. Pure DCIS represented 13% of carcinomas in <35 age group. Patients age ranged 22-35 years (mean=32 years). 89% of DCIS patients were asymptomatic while 78% of DCIS+I presented with nipple discharge or mass. Overall, 25% of all DCIS patients had family history of breast carcinoma with high frequency of BRCA (4 positive/8 tested). History of pregnancy or lactation at diagnosis was only present in DCIS-I group (21%). Mean size of in situ tumor was 1.6 cm (0.3-6cm) for DCIS and 3.5 cm (1.0-8.4 cm) for DCIS+I. DCIS+I were extensive (represented >25% of tumor volume) in 83% (30/36). Nuclear grade of DCIS was 3 in 34/47 (72%). Compared to a group of 278 consecutive DCIS cases diagnosed in 6 months period high nuclear grade was significantly more common in DCIS+I group (Chi square, p<0.01), but not in DCIS group.

DCIS vs. DCIS-I vs invasive carcinoma: immunohistochemical phenotype and DCIS grade

	Luminal A,B	HER-2+	Triple -	KI-67>10%	DCIS grade 1/2/3
Invasive (n=19)	53%	18%	29%	N/A	N/A
DCIS+I (n=38)	65%	16%	19%	80%	3/18/79 (%)
DCIS (n=9)	86%	14%	0	17%	10/45/45 (%)

Basal-like phenotype (triple-/CK5/6+) was seen in DCIS+I (3/38, 8%) but not in DCIS.
Conclusions: The results suggest the possibility that two types of DCIS exist in young women; one with high nuclear grade, high proliferation index, and phenotypes similar to invasive carcinoma that quickly progresses to invasion. The second type of DCIS presents as an asymptomatic lesion, not associated with pregnancy or lactation, is ER+ with low proliferation rate and needs longer time to progress to invasive carcinoma.
Category: Breast

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 28, Monday Morning