Rare case of hemangiopericytoma responds to sunitinib.

Hemangiopericytoma (HP) is a rare mesenchymal tumor associated with the capillary wall. We describe a 62-year-old man with a 20-year history of recurrent metastatic HP, in which a favorable clinical benefit was observed with sunitinib, an oral VEGFR, and PDGFR kinase inhibitor. Disease progression was evident during the 3 months before starting sunitinib therapy. Radiologic evaluation indicated that metastatic lesions in the lungs and pelvis remained stable during the 6 months on sunitinib therapy. Histologic analysis of the tumor 3 weeks after active sunitinib therapy did not reveal tumor necrosis, but recanalized thrombi within tumor blood vessels indicated previous tumor insult. Additional studies are warranted to confirm the possible effects of sunitinib in controlling widespread metastatic HP.