A look towards the clonal origin of metastatic pulmonary carcinosarcoma: Report of a patient with an unexpected long-term survival.

We depicted a model of how a squamous cell carcinoma can differentiate during its natural history into sub-clonal populations with different features and may ultimately result in a neoplasm (i.e. pulmonary carcinosarcoma) showing clonal heterogeneity. Our data might contribute to a better understanding of the pathogenesis and molecular mechanisms of this rare tumor and open new ways for a more tailored approach.