A uterine leiomyoma in which a leiomyosarcoma with osteoclast-like giant cells and a metastasis of a ductal breast carcinoma are present.

Leiomyosarcoma of the uterus is a rare tumor, and the presence of osteoclast-like giant cells in this tumor is even rarer. A leiomyosarcoma arising in a leiomyoma is also quite unique. Breast cancer metastasizing to the uterus is seldom seen as well. A 70-year-old woman presented with metastasized breast cancer to the bones. An evaluation of the computed tomographic scan was made, which showed an enlarged uterus with a tumor. The tumor was a leiomyoma in which a leiomyosarcoma with osteoclast-like giant cells as well as a metastasis of a ductal breast carcinoma was present. To our knowledge, this is the first report of a leiomyosarcoma containing osteoclast-like giant cells, present in a leiomyoma, in a uterus also containing a ductal breast cancer metastasis present in the leiomyoma and myometrium.