Metaplastic breast carcinoma with mesenchymal differentiation: A case series

ABSTRACT The metaplastic breast carcinoma is a rare malignancy with an incidence of 5% of all breast tumors. Metaplastic carcinoma of the breast with mesenchymal differentiation (MCMD), previously known as carcinosarcoma, is a very rare and aggressive tumor that has been recently classified as a subtype of metaplastic breast carcinoma. It accounts for 0.08%–0.2% of all breast cancers, with only a few cases reported in the literature. Metaplastic breast carcinoma most often affects women over 50 years of age, with an average age between 55 and 60 years. We report three cases of metaplastic breast carcinoma with mesenchymal differentiation presented at our hospital. Patients were in their 4th decade. All patients presented with a fast-growing large mass and were treated surgically (mastectomy), with the final histopathological diagnosis of MCMD.