RT Journal Article SR Electronic T1 2022-RA-1632-ESGO Breast carcinosarcoma: a report of an extremely rare entity with a review of the literature JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A217 OP A217 DO 10.1136/ijgc-2022-ESGO.469 VO 32 IS Suppl 2 A1 Chalouati, Takoua A1 Ghalleb, Montassar A1 Jellali, Amani A1 Houissa, Ines A1 Saadallah, Fatma A1 Zemni, Ines A1 Slimane, Maher A1 Rahal, Khaled YR 2022 UL http://ijgc.bmj.com/content/32/Suppl_2/A217.2.abstract AB Introduction/Background Breast metaplastic carcinoma with mesenchymal differentiation, or carcinosarcoma, is a biphasic malignant tumor. It is composed of malignant epithelial and mesenchymal components. It accounts for less than 1% of all breast malignancies.Our aim was to discuss the clinical aspect, the anatomopathological characteristic, and the evolution of this rare entity.Methodology We report nine cases of breast carcinosarcoma followed up at Salah Azaiez institute of oncology in Tunis between 2004 and 2022.Results Our study enrolled nine female patients. The median age was 59 years. One patient had a medical history of breast carcinoma, treated 4 years before developing the carcinosarcoma. In six cases, the tumor was localized in the left breast and in the right side in three cases. Clinically, four patients had T2 tumors, one a T3, three a T4b, and one a T4d. The median size was 8 cm. In the histology, The tumor was triple negative in all cases. Eight patients had radical surgery.conservative surgery was performed in one case. The ninth patient had an adjuvant treatment with chemotherapy and radiation therapy. Metastatic recurrence to the lung and the liver was noted in two cases. The follow-up of the 7 other patients showed no signs of local or distant relapse.Conclusion Breast carcinosarcomas are rare and aggressive entities. Their clinical and radiological aspects are non-specific. The treatment usually associates surgery to chemotherapy and radiation. Hormonal therapy has no place due to the usual absence of hormonal receptors.