Meningeal hemangiopericytoma (HPC) and mesenchymal chondrosarcoma are aggressive neoplasms with a propensity to involve the meninges and dura. In addition to similar clinical presentations, both meningeal HPC and mesenchymal chondrosarcoma share overlapping morphologic features, including ovoid cells, variable collagen deposition, and a branching vascular pattern. Recently, a novel HEY1-NCOA2 fusion was reported as a recurrent event in mesenchymal chondrosarcomas.Thirteen mesenchymal chondrosarcomas and 18 meningeal HPCs were identified from surgical pathology archives, and the tumors were evaluated for HEY1-NCOA2 fusion with reverse transcriptase-polymerase chain reaction (RT-PCR).HEY1-NCOA2 fusion transcript was detected in all six cases of mesenchymal chondrosarcoma but in none of the meningeal HPC cases (0/11) that were evaluable with RT-PCR.These results show that (1) meningeal HPC and mesenchymal chondrosarcoma are distinct at the molecular level, and (2) the identification of HEY1-NCOA2 can be used as an auxiliary diagnostic tool to differentiate these entities.