• The Journal of the Korean bone and joint tumor society
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• v.20 no.2
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• pp.89-93
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• 2014

Clear cell chondrosarcoma is a very rare malignant bone tumor that shows a strong predilection for the epiphysis or metaphysis of long bones. Many studies have reported that the proximal end of the femur is the most commonly affected site, followed by the proximal end of the humerus. Histopathologically, tumor cells of this type have centrally located round nucleoli with clear cytoplasm and a distinct cytoplasmic membrane. Generally, clear cell chondrosarcomas is not confused with conventional chondrosarcomas. However, when it involves the diaphysis in long bones, diagnosis can be hindered, as only three reports of this exist in the literature. We report herein an unusual case of clear cell chondrosarcoma of the tibial diaphysis in a 42-year-old male.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.2
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• pp.155-159
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• 2009

Clear cell chondrosarcoma is a rare, low-grade variant of chondrosarcoma that comprises approximately 2% of all chondrosarcomas. This tumor usually involves the epiphysis and epimetaphysis of long bones, especially the proximal part of the femur or humerus, whereas involvement of the scapula is rare. It occurs at any age, but the peak is third to fifth decade, and is rarely seen in the first and second decades of life. Histologically, tumor cells with abundant clear cytoplasm and benign giant cells are usually found. We report on a case of clear cell chondrosarcoma of the scapula in an 8-year-old girl.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.105-112
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• 2007

Purpose: Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in various human malignancies to include various bone and soft tissue tumors. However, little is known with regard to COX-2 expression patterns in chondroid tumors. Materials and Methods: Immunohistochemistry assays were performed for COX-2 in enchondromas (n=10), chondroblastomas (n=11), chondromyxoid fibromas (n=5), conventional chondrosarcomas (n=17), clear cell chondrosarcomas (n=7), and mesenchymal chondrosarcomas (n=6). Results: Among the benign chondroid tumors, chondroblastomas revealed characteristic strong positivity in 6 of 11 cases(54.5%). All enchondromas and chondromyxoid fibromas were negative except in one case. In conventional chondrosarcomas, three cases(17.6%) were strongly reactive with COX-2 and all positive cases represented grade III chondrosarcomas. Clear cell chondrosarcomas were found to be focally positive in two cases(28.5%), while all mesenchymal chondrosarcomas were negative. Conclusions: These findings suggest that COX-2 overexpression in conventional chondrosarcoma may represent an advanced histologic grade. Interestingly, expression of COX-2 in chondroblastomas could be an important factor for inducing peritumoral inflammatory changes in these specific tumors.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.2
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• pp.130-137
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• 2009

Purpose: STAT3 is an oncogene that regulates critical cellular processes, and its constitutive activation has been demonstrated to correlate with biological and clinical features in many types of human malignancy. Materials and Methods: In this study, STAT3 activation was assessed in variable benign and malignant chondroid tumors in bone by immunohistochemistry using a monoclonal antibody specific for $tyrosine^{705}$-phosphorylated STAT3 ($pSTAT3^{tyr705}$). Results: Among conventional chondrosarcomas (n=17), three cases(50%) of grade III chondrosarcomas were pSTAT3-positive. All grade I and II chondrosarcomas were pSTAT3-negative. This pSTAT3 positivity according to the histologic grade was statistically significant (p=0.0432). Two cases(50%) of clear cell chondrosarcomas were pSTAT3-positive. Six cases (50%) among 12 benign chondroid tumors(6 enchondromas, 3 chondroblastomas, and 3 chondromyxoid fibromas) were also $pSTAT3^{tyr705}$-positive. Conclusion: In conclusion, STAT3 activation is associated with higher tumor grade in conventional chondrosarcomas. Our results suggest that STAT3 is activated in a subset of benign and malignant chondroid tumors, and may support the extension of the cancer stem cell hypothesis to include tumors of cartilaginous lineage.