[38] Do Meningeal Hemangiopericytoma and Mesenchymal Chondrosarcoma Belong to the Same Biologic Spectrum? A Study of HEY1-NCOA2 Fusion

Karen Fritchie, Long Jin, Ana L Ruano, Andre M Oliveira, Brian P Rubin. Mayo Clinic, Rochester, MN; Cleveland Clinic, Cleveland, OH

Background: Meningeal hemangiopericytoma (meningeal HPC) is an aggressive neoplasm characterized by high rates of local recurrence and extracranial metastases. Although earlier classifications have suggested a relationship to variants of solitary fibrous tumor and meningioma, more recent work has shown that meningeal HPC is a distinct entity with an uncertain pathogenesis. Mesenchymal chondrosarcoma is a sarcoma which may involve both skeletal and extraskeletal sites but has a predilection for the meninges. In addition to similar clinical presentations, both meningeal HPC and mesenchymal chondrosarcoma share overlapping morphologic features, including oval to slightly spindled cells, variable collagen deposition and a branching, “staghorn” vascular pattern. Recently, a novel HEY1-NCOA2 fusion was reported as a recurrent event in mesenchymal chondrosarcomas. In contrast, no consistent cytogenetic or molecular aberration has been found in meningeal HPC.
Design: Thirteen mesenchymal chondrosarcomas and 18 meningeal HPCs were identified at the Mayo Clinic and Cleveland Clinic surgical pathology archives. RNA was extracted from paraffin-embedded tissues, and the tumors were evaluated for HEY1-NCOA2 fusion by RT-PCR. Controls included three chondroblastomas, two chondromyxoid fibromas, five Ewing sarcomas and five synovial sarcomas.
Results: HEY1-NCOA2 fusion transcript was detected in 6/6 cases of mesenchymal chondrosarcoma but in none of the meningeal HPC cases (0/11). In 7 cases each of mesenchymal chondrosarcoma and meningeal HPC, RT-PCR was uninformative due to RNA degradation. All controls were negative for HEY1-NCOA2 fusion transcript.
Conclusions: Although there is significant clinical and histologic overlap between mesenchymal chondrosarcoma and meningeal hemangiopericytoma, these results show (1) that they are distinct at the molecular level and (2) that the identification of HEY1-NCOA2 can be used as an auxiliary diagnostic tool to differentiate these entities.
Category: Bone & Soft Tissue

Monday, March 4, 2013 1:00 PM

Poster Session II # 16, Monday Afternoon


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