(P030) Metaplastic Breast Carcinoma at a Single Institution: Clinical-Pathologic Characteristics and Outcome

April 30, 2015
Oncology, Oncology Vol 29 No 4_Suppl_1, Volume 29, Issue 4_Suppl_1

Similar to other reported series, the majority of our patients had triple-negative disease, and our patient population did not express the HER2/neu oncoprotein. Our predominant histology was squamous differentiation, whereas heterogeneity in histology is described in the literature. Despite high-grade disease, the outcomes in our study are favorable in comparison with previously reported series, although the follow-up is short.

Sharang Tenjarla, Sheema Chawla, MD, Jiqing Ye, MD, Brittany Heatherington, Lori Medeiros, MD, Peter Bushunow, MD; Rochester Regional Health System

OBJECTIVES: Metaplastic breast carcinomas (MBCs) are rare primary breast malignancies, constituting < 1% of all breast cancers. They are characterized by differentiation of the neoplastic epithelium into squamous cells and/or mesenchymal-like elements. There is a dearth of information on clinically relevant pathologic features and clinical outcomes for these rare tumors.

METHODS: A search of MBCs in the tumor registry and pathology archives of our center was performed. A review of the demographic and clinical-pathologic features and outcomes of all cases of MBC was performed between 2005 and 2014. Cases were reviewed retrospectively after institutional review board (IRB) approval.

RESULTS: A total of 32 cases were retrieved. Median age was 62 years (range: 42–79 yr). The median tumor size was 3.5 cm (range: 0.8–6.7 cm), and 72% (n = 23) of patients had grade 3 tumors. Histology outcomes showed: squamous in 13 (41%), adenosquamous in 4 (12%), osseous and chondroid in 6 (19%), and spindle cell/sarcomatoid in 9 patients (28%); 28 patients (88%) were triple-negative. Human epidermal growth factor receptor type 2 (HER2)/neu overexpression was not seen in any of the patients. A total of 19 patients underwent mastectomy (59%), and the rest underwent breast conservation surgery. The median follow-up was 17.5 months (range: 3–108 mo). Stage distribution was: stage IA in 11 (34%), IIA in 12 (38%), IIB in 7 (22%), and IIIA in 2 (6%) patients. At a median follow-up of 22 months, five patients had recurrence: one with local and four with distant (two brain, one bone, and one with multiple sites), two of whom are alive with disease. Overall, 28 patients (87%) were alive at last follow-up.

CONCLUSION: Similar to other reported series, the majority of our patients had triple-negative disease, and our patient population did not express the HER2/neu oncoprotein. Our predominant histology was squamous differentiation, whereas heterogeneity in histology is described in the literature. Despite high-grade disease, the outcomes in our study are favorable in comparison with previously reported series, although the follow-up is short.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org