neoplastic

Neoplastic is an adjective used in medicine to describe tissue or cells involved in neoplasia, the process that leads to the formation of a neoplasm or tumor. A neoplasm is a new, abnormal growth arising from uncontrolled cell proliferation and usually is clonal in origin. Neoplasms can be benign, growing locally without invading nearby tissues, or malignant, with the capacity to invade surrounding structures and spread to distant sites (metastasis).

Neoplasia results from genetic and epigenetic alterations in cells, including mutations in oncogenes and tumor suppressor genes, chromosomal changes, and modifications to DNA and chromatin. These alterations can confer growth autonomy, resistance to cell death, sustained angiogenesis, and, in malignant cases, invasive and metastatic behavior. The tumor microenvironment and immune surveillance also influence progression.

Classification of neoplasms is typically by tissue of origin and behavior. Epithelial neoplasms are called carcinomas, connective tissue neoplasms are often sarcomas, and hematopoietic neoplasms include leukemias and lymphomas. Benign neoplasms, such as lipomas or adenomas, remain localized and do not invade or metastasize, whereas malignant neoplasms pose higher clinical risk due to their invasive and disseminating capabilities.

In pathology, the term neoplastic is used to describe tissue showing neoplastic transformation, as opposed to non-neoplastic processes like inflammation or reactive hyperplasia. Dysplasia describes abnormal cellular architecture that may precede neoplasia and confer increased risk of progression to cancer.