[292] Mucinous Carcinoma of Breast: A Retrospective Review of 100 Cases over 9 Year Period with Emphasis on Axillary Staging

A Ranade, R Batra, J Balderacchi. St Lukes Roosevelt and Beth Israel Medical Center, New York, NY

Background: Pure mucinous carcinoma of breast (PMBC) has a better prognosis than mixed mucinous carcinoma (MMC). Although most studies claim this, reports of lymph node (LN) and distant metastases exist in PMBC. We evaluated patient demographics, pathological features and receptor status of mucinous breast carcinoma to address some of these questions.
Design: Two broad categories of a PMBC (n=45) with more than 90% mucinous component and a mixed type (n=55), with 50 to 90 % mucinous component were studied. PMBC was further subclassified as hypocellular/type A (n=37) and hypercellular/type B (n=8) based on the amount of mucin and cellularity. A retrospective analysis of these cases diagnosed at the three hospital centers between 2000 to 2009 was done. Clinicomorphological and limited prognostic features were compared. No patient follow up was done.
Results: Mean age at diagnosis in PMBC and MMC was 60 years (range 34-91), and 63 years (39-90) respectively. Mean tumor size in PMBC and MMC was 1.65 cm (range 0.2-3.5) and 2.5 cm (0.1-9.5) respectively. Mean age in type A and B was 75 and 55 years while mean tumor size was 1.4 and 1.9 cm respectively. Surprisingly we had only 1 case of PMBC with mucocele like lesion. Ductal carcinoma in situ (DCIS) was present in 58% of PMBC and 74% MMC. Well differentiated PMBC were 55.5% (64% type A and 13% B), moderately differentiated 33.3 % (27% type A and 63% B), while poorly differentiated were 4.4% (0% type A and 25% B). Sentinel lymph nodes (SLN) were positive in 18.5% PMBC (15% type A and 29% B), and 16% MMC. Non sentinel lymph node (NSLN+) was in 14% PMBC (10% type A and 25% B) and 39% MMC. All PMBC with LN(+) had micrometastasis while 40% MMC had macrometastasis. Lymphovascular invasion (LVI) was seen in 6% and 22% of PMBC and MMC respectively. 95% PMBC were ER(+), 84% PR(+) and 11% Her2(+) while, 91% MMC were ER (+), 87% PR(+) and 33% Her2(+).
Conclusions: In our study, SLN (+) was observed in a similar % of PMBC and MMC. Hence we emphasize a positive role of axillary staging in PMBC. Rather than tumor size, grade and nodal status should predict outcome and management in PMBC as most patients with LN (+) and high histological grade in our study, had a tumor size between 2 to 3 cm. Although limited by number of cases and statistical significance, type B was less favorable than A, comparing LN(+), histological grade, LVI and mean age. Her2(+) was higher in our study (11%) but this could relate to ploidy status of tumor, which requires further studies.
Category: Breast

Tuesday, March 23, 2010 8:45 AM

Platform Session: Section C, Tuesday Morning

 

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