Two Tumors of Soft Tissues Resembling Tumors of Bone

Abstract

The occurrence in soft tissues of neoplasms simulating tumors of bone has long been known to pathologists. Displacement of embryonic tissue has frequently been invoked to explain such anomalous pictures. A tenuous connection with the nearest skeletal unit has as often been postulated. A better understanding of the histogenesis if not of the mechanism of bony metaplasia has, however, enabled us definitely to discard such forced hypotheses. If the connective-tissue cell may be regarded as capable of bone formation—and this fact may no longer be disputed—it is no more than to be expected that the growth inhibitors normally present should occasionally fail of their function and permit a bony new growth to occur. This takes place even in the (presumably) perfectly regulated proliferation of normal bones. It would be most surprising, therefore, if bony tissue, which owes its very existence to a disturbance in cellular multiplication and metaplastic differentiation, should not be capable of assuming a neoplastic character. The “osteoma” and “chondroma” of soft tissue are extremely frequent, although seldom entitled to the name. A group of osteoplastic tumors in soft tissue has recently been reported by Mallory (1). None, however, was of the type herein discussed. It is the opinion of the author that an adequate survey would reveal every known type of bone tumor as having its counterpart in soft tissue. Two such cases are herewith presented.