The origin of intracranial fibrosarcoma

Summary

To elucidate the cellular derivation of intracranial fibrosarcoma, specimens from two cases of primary sarcoma and two cases of secondary, radiation-induced sarcoma in the cranium were examined by light and electron microscopy and histochemical techniques. The findings were carefully compared with those in four cases of benign fibroblastic meningioma. All the intracranial sarcomas examined in this study were localized on the cerebral surface and invaded the dura mater and brain.

The histology of these tumors closely resembled that of fibrous fibrosarcoma described by Christensen and Lara [2]. The microscopic features of primary sarcomas were characterized by a spoke wheel arrangement of tumor cells, intercellular deposits of variable amounts of collagen fibers and the presence of many xanthoma cells. Secondary sarcomas presented tumor cells arranged in parallel interlacing bundles. An island of tumor tissue with the characteristics of benign meningioma was disclosed in a primary sarcoma. In meningioma was disclosed in a primary sarcoma. In electron micrographs, sarcoma cells showed ultrafine structures characteristic of meningothelial cells, including interdigitated cytoplasmic processes, desmosomes and/or half desmosomes, and abundant intracytoplasmic filaments. Basement membrane or an analogous substance, which is very unusual in the meningioma, were identified in some specimens of our primary sarcomas and fibroblastic meningioma. In the histochemical study, the activities of acid phosphatase and non-specific esterase showed no significant differences between the sarcoma cells and the meningioma cells.

On the basis of morphological and histochemical findings, it is concluded in this study that fibrous fibrosarcomas in the cranium are of meningothelial derivation and therefore should be included in the category of malignant meningioma.