Carcinosarcoma of the breast—a rare entity with a fatal prognosis. Case report

Background: Metaplastic breast carcinomas are a heterogeneous group of neoplasms that exhibit a poor prognosis compared with invasive ductal carcinoma. They correspond to <1% of all malignant neoplasms of the mammary gland. They usually present as highgrade tumors with a lower rate of lymph node metastases and decreased expression of estrogen, progesterone and Her2 receptors and increased expression of Her1 and Ki-67. Clinical case: We report the case of a 52-year-old woman who presented with a breast carcinosarcoma with a fungated, ulcerated, polypoid left breast tumor that was 18 cm in diameter with lymph node metastases at diagnosis. She received multimodal management with neoadjuvant chemotherapy followed by mastectomy and adjuvant chemotherapy. She presented with disease progression with lung metastases and local massive recurrence and eventually died from complications associated with the disease. Conclusions: Metaplastic carcinomas of the breast are extremely rare entities. Due the nature of disease and presentation, the prognosis is poor in these patients. There are several histological subtypes based on studies using hematoxylin and eosin and immunohistochemical stains. This entity requires multimodal therapy (surgery, radiotherapy and chemotherapy) for best results.