[303] Mucinous Carcinoma of the Breast: Clinicopathological Analysis with Emphasis on Biomarker Expression and Incidence of Metastasis and Recurrence

Natalie Webster, Ossama W Tawfik, Fang Fan. University of Kansas Medical Center, Kansas City, KS

Background: Mucinous carcinomas are typically ER and PR positive and do not usually overexpress the HER2 protein. They are generally associated with low rates of local and systemic recurrence. The goal of this study is to assess the clinicopathologic features and biomarker expressions of breast mucinous carcinoma cases and their association with axillary lymph node metastasis and systemic recurrence.
Design: Cases of pure mucinous carcinoma (>90% mucinous) and mixed mucinous carcinoma (<90% mucinous) of the breast were identified from our surgical pathology files between 1997 and 2012. Histopathologic data, including histologic grade, nuclear grade, and lymph node metastases was collected. The tumor biomarkers expression including ER, PR, and HER2 status was also collected in addition to clinical information such as age, tumor size, and incidence of local recurrence and distant metastasis.
Results: 36 cases of mucinous carcinoma and 13 cases of mixed mucinous carcinoma were identified. The clinicopathologic data and biomarker profile of these cases are shown in the following table.

Table 1
 Pure Mucinous Carcinoma (n=36)Mixed Mucinous Carcinoma (n=13)
Mean Age (years)67 (range 42-88)56 (range 41-74)
Mean Tumor Size (cm)1.5 (range 0.1-6.8)3.0 (range 0.8-10.5)
Nuclear Grade1: 191: 0
 2: 172: 10
 3: 03: 3
Histologic Grade1: 281: 0
 2: 82: 10
 3: 03: 3
Axillary Lymph Node*Positive: 3Positive: 7
 Negative: 27Negative: 5
Follow-up (months)41 (range 0-99)46 (range 9-116)
Recurrence*Yes: 2Yes: 3
 No: 27No: 3
Death*Yes: 0Yes: 0
 No: 29No: 13
ER/PR/HER2 StatusER+/PR+/HER2-: 34ER+/ PR±/HER2-: 10
 ER +/PR -/HER2-: 2ER+/ PR±/HER2+: 3
* Complete clinical and/or pathologic data was not available for all cases.

Conclusions: While all pure mucinous carcinomas and the majority of mixed mucinous carcinomas were ER+/Her2-, some cases of mixed mucinous carcinomas were ER+/Her2+. PR expression was variable. Despite having an overall good prognosis, a small percentage of pure mucinous carcinoma cases had positive axillary lymph nodes and exhibited late distant metastases. Mixed mucinous carcinomas had a worse prognosis with more frequent lymph node metastases and systemic recurrence. Negative PR and/or positive Her2 expression appear to be associated with a worse outcome.
Category: Breast

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 43, Wednesday Morning


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