Two uncommon cases of uterine leiomyosarcomas displaying heterologous osteosarcomatous de-differentiation

Uterine leiomyosarcomas uncommonly arise on a background of leiomyomas. Still rare is osteosarcomatous dedifferentiation in such tumors. A 60-year-old female presented with abdominal pain and underwent radiological imaging that disclosed a large, well-defined, heterogeneously enhancing uterine tumor. She underwent total abdominal hysterectomy with bilateral salpingectomy. Another, 38-year-old female with the complaints of infertility underwent myomectomy for multiple fibroids. Multiple tumor sections from both the cases showed leiomyomas along with leiomyosarcomas and osteosarcomatous dedifferentiation. Immunohistochemically, both the tumors displayed diffuse expression of smooth muscle markers in areas of leiomyomas, reduced expression of the same in areas of leiomyosarcoma and absent expression in areas of osteosarcomatous dedifferentiation. Unfortunately, both the cases were lost to follow-up. Present cases constitute as rare documentations of uterine leiomyosarcomas, arising on a background of leiomyomas and exhibiting osteosarcomatous dedifferentiation. The value of identifying these tumor components, with extensive tumor sampling relates to their relatively aggressive clinical course