Abstract
Heterotopic ossification (HO) within tissues involved by a pathologic process is a well-recognized phenomenon. It is most frequently observed in atherosclerotic plaques, in soft tissue around joints, and in the central nervous system. Less frequently, carcinomas and some benign neoplasms will undergo heterotopic ossification. We report on a case of high-grade Leiomyosarcoma with osseous differentiation. The identification of areas with osseous differentiation in soft tissue sarcomas can be of clinical importance because of a possible change in oncologic treatment strategies.