May also be called: Cancer; Malignant Tumor; Metastatic Tumor; Carcinoma

A malignant neoplasm (NEE-oh-plaz-um) is a cancerous tumor, an abnormal growth that can grow uncontrolled and spread to other parts of the body.

More to Know

Tumors, or neoplasms, are groupings of abnormal cells that cluster together to form a mass or lump. They're formed when cells divide and grow excessively, and they can be benign (not cancerous) or malignant (cancerous).

A cancerous tumor (malignant neoplasm) can grow unchecked, invade healthy tissue and metastasize (spread), or spread from the place where it starts to other parts of the body. If it goes untreated and continues to spread, a malignant neoplasm can interfere with organ function and become life threatening.

Treatment depends on the type of cancer and how far it has progressed. If the cancer is limited to one area and hasn't spread, the tumor may be removed through surgery. Other common treatments include chemotherapy, which kills cancer cells throughout the body, and radiation therapy, which kills cancer cells in a specific area of the body.

Keep in Mind

The sooner a malignant neoplasm is detected, the more effectively it can be treated, so early diagnosis is important. Many types of cancer can be cured. Treatment for other types can allow people to live for many years with cancer.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.