Carcinosarcoma of salivary glands with unusual stromal components. Report of two cases and review of the literature.

Carcinosarcomas are rare neoplasms that exhibit heterologous malignant epithelial and stromal components. We report two cases of salivary gland carcinosarcoma with immunohistochemical analysis and clinical follow-up that provide insights into the pathogenesis and behavior of these tumors. In one case, a 51-year-old black woman had a 15-year history of a hard, asymptomatic, infraauricular mass that recently had undergone rapid growth. The tumor showed adenocarcinoma and osteosarcoma. She died 9 months after diagnosis. In another case, a 78-year-old white woman had a large soft palate mass that had been present for several years and had recently caused dysphagia. The tumor showed adenocarcinoma and leiomyosarcoma. The patient is alive at 9 months follow-up. Although malignant epithelial and stromal components characterize carcinosarcomas, immunohistochemical studies suggest that both elements are derived from a common precursor cell, possibly of myoepithelial origin. These cases support this concept and perhaps suggest a spectrum of differentiation that this precursor cell may exhibit.