MESENCHYMAL CHONDROSARCOMA - A CLINICOPATHOLOGICAL AND FLOW CYTOMETRIC STUDY OF 13 CASES PRESENTING IN THE CENTRAL-NERVOUS-SYSTEM

BAGKGROUND. Mesenchymal chondrosarcomas arising in the central nervous system are extremely rare. Morphologic features have not been found t o correlate reliably with prognosis. METHODS, Eight intracranial and f ive intraspinal mesenchymal chondrosarcomas were reviewed with regard to location, treatment, and long term follow-up data. The histopatholo gic and immunohistochemical results, including Ki-67 nuclear staining frequency, were critically reviewed, and deoxyribonucleic acid content was analyzed by flow cytometry. RESULTS, Microscopically, all 13 case s were remarkably similar. Immunoreactivity in the small cell componen t included vimentin in 100%, and cytokeratin and glial fibrillary acid ic protein in 25% of cases. S-100 immunoreactivity was noted in the ca rtilaginous component of 100% of cases, and in rare cells in the small cell component along the interface. Flow cytometry of the eight tumor s studied revealed a diploid pattern in six, aneuploidy in two, and a wide range of S-phase fractions (0-36.5%). CONCLUSIONS. Review of the literature and the findings of the current series indicates that mesen chymal chondrosarcomas presenting in the brain and spinal cord pursue a progressive course that correlates most reliably with extent of surg ical resection. This limited retrospective study also suggests that su rvival maybe shorter for those patients with a high S-phase fraction a nd a high Ki-67 staining frequency.