Bone metastasis in pulmonary sclerosing hemangioma

No abstract available.

Analysis of angiogenic factors and cyclooxygenase-2 expression in cartilaginous tumors: clinical and histological correlation

OBJECTIVES: To study the role of angiogenesis and cyclooxygenase-2 expression in cartilaginous tumors and correlate these factors with prognosis. INTRODUCTION: For chondrosarcoma, the histological grade is the current standard for predicting tumor outcome. However, a low-grade chondrosarcoma can follow an aggressive course-as monitored by sequential imaging techniques-even when it is histologically indistinguishable from an enchondroma. Therefore, additional tools are needed to help identify the biological potential of these tumors. The degree of angiogenesis that is induced by the tumor could assist in this task. Angiogenesis can be quantified by measuring the expression of vascular endothelial growth factor and CD34, and cyclooxygenase-2 can induce angiogenesis by stimulating the production of proangiogenic factors. METHODS: In total, 21 enchondromas and 58 conventional chondrosarcomas were studied by examining the clinical and histopathological findings in conjunction with the immunostaining markers of angiogenesis and cyclooxygenase- 2 expression. RESULTS: The significant variables that were associated with poor outcome were 1) higher-grade chondrosarcomas, 2) tumors that developed in flat bones, and 3) over-expression of CD34 (with a median count that was higher than 5.9 vessels in 5 high power fields). Moreover, CD34 expression (measured using the Chalkley method) revealed significantly higher microvessel density in flat bone chondrosarcomas. DISCUSSION: Previous studies have shown a positive correlation between Chalkley microvessel density and histological grade; however, in our sample, we found that the former is predictive of the outcome. Chondrosarcomas in flat bones have been shown to correlate with a poor prognosis. We also found that CD34 microvessel density values were significantly higher in flat-bone chondrosarcomas. This could explain-at least in part-the more aggressive biological course that is taken by these tumors. CONCLUSIONS: These results provide evidence that CD34 microvessel density in chondrosarcomas can be helpful in predicting patient outcome and may add to our understanding of chondrosarcoma pathogenesis.

Osteocalcin expression in primary bone tumors: in situ hybridization and immunohistochemical study

Osteocalcin is one of the most abundant noncollagenous proteins found in adult bone. It is a highly conserved gamma-carboxyglutamic acid-containing protein that is believed to be produced exclusively by osteoblasts. In this study, intracellular and extracellular localization of osteocalcin in osteosarcoma was examined with anti-osteocalcin antibody and in situ hybridization using a synthetic oligonucleotide. Immunohistochemically, osteoblastic osteosarcomas were all positive for osteocalcin. The chondroblastic osteosarcomas were positive on the neoplastic chondrocytes. The five fibroblastic osteosarcomas out of seven were positive for osteocalcin immunostaining over the neoplastic spindle cells. Five cases of osteoblastic osteosarcomas out of seven were positive for osteocalcin in situ hybridization. Two cases of chondroblastic osteosarcomas and three cases of fibroblastic osteosarcomas were positive for in situ demonstration of osteocalcin. The malignant tumor giant cells were positive for osteocalcin immunostaining 83%. They were also positive for in situ hybridization. The benign giant cells in five giant cell tumors and five aneurysmal bone cysts were negative for osteocalcin immunostaining. The benign giant cells in three chondroblastoma and three Paget's disease were positive for osteocalcin. In this study, the osteocalcin in situ hybridization and immunostaining has very important meaning for making differential diagnoses of, especially giant cell rich bone forming tumors.

Expression of p53 protein, PCNA, and Ki-67 in osteosarcomas of bone

Expressions of p53 protein, a product of the tumor suppressor gene were studied in osteosarcomas relating to various prognostic factors. Thirty-four osteosarcomas were investigated immunohistochemically with a monoclonal antibody clone PAb240, which recognizes a common conformational epitope of mutant p53 proteins and another clone PAb1801, which reacts with both wild- and mutant-type p53 proteins. The results were compared with expressions of proliferating cell nuclear antigen (PCNA) and Ki-67 providing a simple method for the assessment of growth fractions of tumors. PAb240 stained nuclei and cytoplasm of tumor cells in 8 of 34 osteosarcomas (23.5%), whereas PAb1801 reacted in all 34 osteosarcomas (100%). Fifteen tumors (44.1%) showed positivity for PAb1801 in more than half of the tumor cells. Twelve patients were alive and thirteen were dead. Tumors from 9 patients (75%) who survived revealed only focal positive immunoreactions with PAb1801 and tumors from 6 patients (46.1%) who died revealed diffuse reactions. Twelve cases (35.3%) showed a high PCNA index (> 40%) and fibroblastic osteosarcomas revealed the highest PCNA positivity. Twenty-two cases (64.7%) revealed a very low Ki-67 index (less than 10%) and Ki-67 index showed a good correlation with PCNA positivity (r = 0.6247). Expressions of both wild-and mutant-type p53 protein, PCNA, and Ki-67 were not correlated with other clinical or pathological parameters.