Case Report of the positive exostosin-1 without B-cell lymphoma-2 gene expression of giant cell tumor lesion in hereditary multiple exostosis

INTRODUCTION: The giant cell tumor, in which BCL-2 gene was expressed only in its malignant transformation, is a benign, primary skeletal neoplasm with variable biologic aggressiveness. The is of the giant cell tumor. A coexistence with hereditary multiple exostosis with expression of EXT-1 is very rare. The correlation between giant cell tumor in hereditary multiple exostosis is still not clearly determined. PRESENTATION OF CASE: A 31-years-old female presented with pain and lump on her left wrist and a coexistence of non tender multiple lump in the right and left knee. A wide excision of the tumor and reconstruction using non vascularized fibular graft was performed, followed by histopathology and immunohistochemistry of EXT-1 and BCL-2. DISCUSSION: In this case, the tumor showed negative BCL-2 and positive EXT-1 gene expression. Giant cell tumor and hereditary multiple exostosis also demonstrated associations of chromosomes 11 with a different pathological process. CONCLUSION: Giant cell tumor in hereditary multiple exostosis revealed positive EXT-1 without BCL-2 expression. It still need more investigation to confirm the relationship between these tumors.