[225] Squamous Cell Carcinoma of the Breast: A Clinicopathologic Study of 21 Cases.

Anupma Nayak, Savitri Krishnamurthy, Yun Wu, Michael Z Gilcrease. The University of Texas M.D. Anderson Cancer Center, Houston

Background: Primary squamous cell carcinoma (SCC) of the breast is a rare form of invasive breast carcinoma defined as having greater than 90% squamous differentiation. Studies evaluating the clinical behavior of this tumor have yielded inconsistent results. Further, the biological behavior of this tumor has not been adequately studied in the context of its varying histomorphology. Our aim was to evaluate the clinical and histological features of this tumor and to correlate these with disease outcome.
Design: A total of 21cases of primary SCC of the breast were selected for analysis from the computerized database of the Department of Pathology between the years 1985 and 2010. Exclusion criteria included non-availability of histology slides for review and tumors with less than 90% squamous differentiation. Clinical and histological features were evaluated and correlated with disease outcome.
Results: The 5-yr overall survival (OS) of patients with primary SCC of the breast was 51% ± 13%. The only statistically significant features associated with OS were patient age and tumor keratinization. Patients greater than 60 yrs of age had decreased OS (log rank, P=0.035). Five-yr survival rate for patients greater than 60 yrs of age and 60 yrs or less was 36% ± 20% and 60 ± 16%, respectively. Patients with tumors having at least focal keratinization had improved OS as compared to patients with nonkeratinizing tumors (87% ± 12% vs. 26% ± 15%; log rank, P=0.027). There was a trend for patients with cystic tumors and those with associated DCIS to have improved OS. In contrast, patients with tumors having spindle cell metaplasia and/or acantholytic change showed a trend towards decreased survival, but the differences were not statistically significant. Most tumors (17/21) were moderately or poorly differentiated, most had a high nuclear grade (15/21), and most were Nottingham histologic grade 3 (17/21). Among the few patients with tumors that were well differentiated or with intermediate nuclear or histologic grade, there were no deaths during the follow-up period, but the number of patients in these categories was insufficient to show statistical significance. Lymph node status, mitotic rate, tumor necrosis, clear cell change, and the presence of a pleomorphic component were not associated with OS.
Conclusions: Primary SCC of the breast tends to be aggressive, particularly in patients over 60 yrs of age, but the presence of at least focal keratinization is associated with significantly improved overall survival.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 48, Monday Afternoon


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