Matrix-Producing Carcinoma of the Breast: Case Report.

Matrix-producing carcinoma (MPC) is an uncommon variant of metaplastic carcinoma. It was first described by Wargotz and Norris in 1989 as invasive breast carcinoma with direct transition to cartilaginous stroma without intervening spindle cell component. Since then, several studies, mostly in the form of case reports or case series, have been reported and the origin of tumor cell, importance of appropriate terminology for the tumor, histopathological differential diagnosis, benign breast lesions that the tumor could correlate with, and prognosis and consequently the treatment modalities have been discussed. A 43-year-old woman referred to our clinic with a lump in her left breast. Physical examination and radiological findings were consistent with malignancy. Core biopsy of the lesion was reported as "invasive breast carcinoma" and then breast-conserving surgery with sentinel lymph node dissection were performed. The case was diagnosed as MPC of the breast. The literature findings imply epithelial cell (ductal and/or myoepithelial) nature of this tumor. The prognosis is still controversial. Histopathological evaluation of sufficiently sampled surgical excision material is important to recognize and make a correct diagnosis.