Meningeal mesenchymal chondrosarcoma. Report of 8 cases with review of the literature

Abstract

This paper reviews 8 personally examined cases of primary meningeal mesenchymal chondrosarcoma and 4 similar cases previously reported by others. The clinicopathologic features of these extraosseous intracranial and intraspinal examples are similar to those of other extraskeletal mesenchymal chondrosarcomas. The tumor occurred most often in the second and third decades, showed a moderate tendency to local recurrence (5 of 12 cases) and occasionally metastasized to the lungs (1 case). Both intracranial and intraspinal tumors occurred with equal frequency, but the former, probably due to the later onset of symptoms, had the worse prognosis. Microscopically, they are composed of primitive undifferentiated mesenchymal cells and frequently well-defined islands of hyaline cartilage. There is an apparent correlation between the frequency of mitotic figures and the likelihood of recurrence and metastasis. Electron microscopic study of one example revealed morphologic features similar to those previously described by others and supports the conclusion that the neoplastic cells represent primitive precartilaginous mesenchyme displaying focal cartilaginous differentiation.

Reappraisal of mesenchymal chondrosarcoma: novel morphologic observations of the hyaline cartilage and endochondral ossification and β-catenin, Sox9, and osteocalcin immunostaining of 22 cases

“…As previously noted, CNS is the most common extraosseous site. The largest series of CNS examples are by Rushing et al [8] (n = 13 patients) and Scheithauer and Rubinstein [10] (n = 8 patients). Purportedly of dural origin, these tumors probably arise from pluripotent mesenchymal cells within the meninges.…”

“…In our series, mesenchymal chondrosarcoma demonstrates chondrocytes in all stages of chondrogenesis, in a linear, logical progression to cell death and acquired osteoblastic phenotype, resulting in central endochondral ossification. Others have previously mentioned the "well-differentiated" or "bland" appearance of the hyaline cartilage component in these tumors [2,5,7,8,10,11]. Some have stated that the cartilage appeared to be either "benign" [2] or "less pleomorphic" compared to other types of chondrosarcoma [5].…”

“…Mesenchymal chondrosarcoma, a rare high-grade malignant tumor of purported cartilage phenotype [1][2][3][4][5], is predominantly intraosseous [2,6,7]; extraskeletal sites are rare, yet brain and spinal cord are the most common extraskeletal locations [3,[8][9][10][11]. Histologically, mesenchymal chondrosarcoma has a characteristic biphasic pattern composed of a cellular poorly differentiated small round blue cell component interspersed with islands of well-differentiated hyaline cartilage.…”

Mesenchymal Chondrosarcoma arising in the Central Nervous System: A Diagnostic Pitfall

“…Morphological assessment of both extraosseous and osseous lesions showed the same characteristic biphasic appearance. 11 The two elements are composed of islands of hyaline cartilage and sheets of undifferentiated round to oval small cells. 5,6,9 The cartilaginous component is welldifferentiated and may appear as benign hyaline cartilage, low-grade chondrosarcoma.…”

Primary Intracranial Myxoid Chondrosarcoma: Report of a Case and Review of the Literature

“…Theoretically, a chondrosarcoma should originate from the mesenchymal tissues, like cartilage, therefore, those arising from the skull base are quite natural. Intracranial chondrosarcomas are also thought to arise from the mesenchymal elements of the central nervous system, such as, the primitive multipotential mesenchymal cells or their mature descendents (fibroblasts, meningeal cells, and pial cells) located within the leptomeninges, the pia-arachnoid surrounding blood vessels or in the vessel walls, the stroma of the choroid plexus and aberrant embryonal cartilagenous rests (4,7,(9)(10)(11)(12)(13)(14)(15)(16). In the case of primary intraparenchymal chondrosarcoma, misplaced embryonal cartilagenous rests or primitive multipotential mesenchymal cells in leptomeningeal sheaths around vessels or the vessel walls have been suggested to be origins without definitive evidence (3,5,7,8,10,(17)(18)(19)(20)(21).…”