Malignant osteoclast-like giant cell tumor associated with a uterine leiomyosarcoma

An unusual case of osteoclast-like giant cell tumor associated with a leiomyosarcoma of the uterus is described. The mononuclear cell component of the giant cell tumor was cytologically malignant and the giant cell tumor was present in a biopsy of vaginal recurrence. The patient expired 17 months after diagnosis with extensive tumor despite surgical and radiation treatment. This is the first report of malignant osteoclast-like giant cell tumor associated with a uterine leiomyosarcoma and only the third report of osteoclast-like giant cell tumor in the uterus.