APA Dictionary of Psychology

n. a new, abnormal growth; that is, a benign or malignant tumor, although the term is generally used to specify a malignancy (see cancer). A neoplasm usually grows rapidly by cellular proliferation but generally lacks structural organization. A malignant neoplasm is usually invasive, destroying or damaging neighboring normal tissues, and can spread to distant sites by the process of metastasis; benign neoplasms are usually encapsulated and do not spread but may damage neighboring tissues by compression. —neoplastic adj.