Papillary Solitary Fibrous Tumor/Hemangiopericytoma: An Uncommon Morphological Form With NAB2-STAT6 Gene Fusion.

Solitary fibrous tumor/hemangiopericytomas (SFT/HPCs) are mesenchymal tumors characterized by "staghorn" blood vessels and collagen deposition. Little is known about SFT/HPCs with papillary architecture. We summarized the clinicopathologic features of 12 patients with papillary SFT/HPCs (8 males and 4 females; median age: 59 years), including 8 previously reported cases.