VWF and sarcoma: Vasuli et al. previously described the immunohistochemical characteristics of pulmonary intimal sarcoma tissues, indicating that the cells of intimal sarcoma were positive for the mesenchymal cell marker, vimentin, negative for the endothelial cell markers von-Willebrand factor (VWF) and CD31, and for the smooth muscle cell marker, α-smooth muscle actin [28].