Neoplasie

Neoplasie, or neoplasia, is a new growth of tissue caused by uncontrolled cellular proliferation that persists even after the original stimulus is removed. Neoplasms can be benign or malignant. Benign neoplasms are usually well circumscribed, grow slowly, and do not invade nearby tissues or metastasize; malignant neoplasms invade and spread to distant sites.

Neoplasia results from genetic and epigenetic alterations that disrupt normal growth controls. Driver mutations in oncogenes and tumor suppressor genes, chromosomal changes, and epigenetic modifications promote sustained proliferation and resistance to cell death. External factors such as tobacco, alcohol, ultraviolet light, infections, chemicals, and radiation increase risk, alongside inherited predispositions.

Classifications reflect tissue of origin: carcinomas (epithelial), sarcomas (mesenchymal), hematologic tumors (lymphomas and leukemias), and other categories like gliomas or melanomas. Benign examples include lipomas and adenomas; malignant examples include adenocarcinomas and osteosarcomas.

Diagnosis typically relies on histopathology from biopsy, with imaging and laboratory tests for staging. Staging uses tumor size, nodal involvement, and distant metastasis (TNM). Treatment may include surgery, radiation, chemotherapy, targeted therapy, or immunotherapy, depending on type and stage.

Prevention focuses on reducing risk factors and screening; some cancers are preventable through vaccination against pathogens like HPV or hepatitis viruses. Prognosis varies widely by cancer type and stage, from potentially curable to advanced disease with limited survival.