Carcinosarcoma of the uterus: immunohistochemical and genetic analysis of clonality of one case

Abstract

Background: Carcinosarcomas of the uterus are characterized by admixtures of malignant epithelial and stromal cells, and their histogenesis remains controversial.

Case: An operated case of carcinosarcoma of the uterus in a 49-year-old woman is reported with clonal analysis. The tumor was composed of carcinomatous, sarcomatous, and transitional elements in the frontal wall of the uterine body and therefore was diagnosed as a carcinosarcoma. On immunohistochemical analysis, the sarcomatous component proved negative for epithelial membrane antigen and keratin while both components were positive for vimentin. Analysis of X-chromosome inactivation showed the same pattern throughout and additionally, the same K-ras and p53 mutations were homogeneously detected. Microsatellite instability analysis showed loss of heterozygosity at D5S346 in the sarcomatous but not the carcinomatous component.

Conclusions: This tumor appears monoclonal in line with the combination tumor theory, with late divergence in genetic alteration in the sarcomatous elements.