A tumor composed of atypical neoplastic, often pleomorphic cells that invade other tissues. Malignant neoplasms usually metastasize to distant anatomic sites and may recur after excision. The most common malignant neoplasms are carcinomas (adenocarcinomas or squamous cell carcinomas), Hodgkin's and non-Hodgkin's lymphomas, leukemias, melanomas, and sarcomas. -- 2004
