[Carcinosarcoma of the breast a rare entity with fatal prognosis. One case report].

BACKGROUND: breast metaplastic carcinomas are a heterogeneous group of neoplasms that exhibit a poor prognosis compared with invasive ductal carcinoma. Correspond less than 1% of all malignant neoplasms of the mammary gland. They usually present as high-grade tumors with a lower rate of lymph node metastases and decreased expression of estrogen and progesterone receptors and Her2 and increased expression of Her1 and Ki-67.

CLINICAL CASE: we report a 52 year old woman with a breast carcinosarcoma presented with a left breast tumor fungated, ulcerated, polypoid and 18 cm in major diameter with lymph node metastases at diagnosis. She received multimodal management with neoadjuvant chemotherapy, followed by mastectomy and adjuvant chemotherapy; she presented progression of the disease with lung metastases and local massive recurrence, eventually died from complications associated to 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 histologic subtypes based on studies of hematoxylin and eosin and immunohistochemical stains. It requires multimodal therapy (surgery, radiotherapy and chemotherapy) for best results.