D2-40 staining in sinonasal-type hemangiopericytoma—further evidence of distinction from conventional hemangiopericytoma and solitary fibrous tumor

D2-40 is a monoclonal antibody, which reacts with a fixative-resistant epitope of lymphatic endothelium. Sinonasal-type hemangiopericytoma (SHP) and tumors of the (conventional) hemangiopericytoma/solitary fibrous tumor family (HP/SFT) are characterized by prominent vasculature. However, data concerning D2-40 labeling of these tumors are very sparse. In the present study, we investigated D2-40 staining in tissue specimens of 17 patients with SHP (male to female ratio of 2.4:1, median age of 63 years) and compared the immunolabeling with 20 cases of HP/SFT, including three SFT cases from nasal mucosa. D2-40 was detected in vascular channels of all SHP patients examined. By contrast, all cases of HP/SFT did not reveal any vascular channel being positive for D2-40, neither in the nasal cases nor in the remaining patients. This study presented for the first time data on D2-40 labeling in a series of SHP, HP/SFT, and supports the distinction of SHP from HP/SFT.