Bone Formation in Metastases of Osteogenic Sarcoma: Report of Case with Metastases to the Brain

Abstract

Occasionally one has an opportunity to study the pathologic aspects of cases which shed considerable light on current conceptions of pathologic processes. The case here described is of double interest. The metastatic nodules secondary to an osteogenic sarcoma of the femur, though not always in contact with bone, were found to be capable of forming osteoid tissue and adult bone within their substance. Furthermore, one of the metastatic nodules in the brain proved to be radiographically visible, an observation hitherto unreported as far as we have been able to learn. Calcification within intracranial tumors has been recognized since Virchow described psammoma bodies in so-called “dural endotheliomas” (meningiomas). In a previous report from this hospital (1) the statement was made that “calcareous deposits have been known to occur in almost every variety of primary new-growths that compromise the intracranial space.” The question of secondary growths was purposely omitted, in the belief that deposit of calcium in a metastatic nodule was most unlikely. The unusually slow growth of metastatic nodules within the brain substance in some instances would theoretically permit the deposit of calcium. As far as we know, however, this has not been described. Actual bone formation in intracranial tumors is of much more rare occurrence, and very few cases, not all of them unquestioned instances of new growth, have been described in the literature. The process is most commonly observed in meningiomas which have undergone regressive change. It seems evident that bone formation in such tumors is not necessarily due to their contact with pre-existing bone, for this process occurs most frequently in meningiomas of the spinal canal, where this situation does not exist.