A low grade malignant neoplasm characterized by the presence of a benign epithelial component (tubular and cleft-like glands) and a low grade sarcomatous component that contains varying amounts of fibrous and smooth muscle tissues. In a minority of cases, the sarcomatous component contains heterologous elements including striated muscle, cartilage, and fat. It occurs in the uterine corpus, ovary, fallopian tube, cervix, and vagina. It may recur and in a minority of cases may metastasize to distant anatomic sites.

A malignant neoplasm arising simultaneously or consecutively in mesodermal tissue and glandular epithelium of the same part. (Stedman, 25th ed)

A tumor that is a mixture of an adenoma (a tumor that starts in the gland-like cells of epithelial tissue) and a sarcoma (a tumor that starts in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue). An example of an adenosarcoma is Wilms tumor.