Tumor

Tumor, or neoplasm, abnormal overgrowth of tissue. These may be benign proliferations, such as fibroid of the womb, or they may be forms of cancer (lymphoma or sarcoma), which are generally malignant. The rate of growth, the tendency to metastasize (spread locally and to distant sites via the blood vessels and lymph system), and systemic effects determine the degree of malignancy. Tumors may present as a lump, by local compression effects (especially with brain tumors), or by systemic effects, including anemia, weight loss, false hormone actions, neuritis, etc. Treatments include surgery, radiation therapy, and chemotherapy.

See also: Cancer.