neoplasias

Neoplasias refer to abnormal tissue growths that form neoplasms (also called tumors). Neoplasms can be benign or malignant. Benign neoplasias grow slowly, usually remain localized, and do not invade adjacent tissues or metastasize. Malignant neoplasias invade surrounding tissues, can spread to distant sites (metastasize), and their growth is often poorly regulated.

Neoplasias arise from genetic and epigenetic alterations that disrupt normal cell growth and death. Driver mutations confer growth advantage to clonal cell populations. Features associated with malignant neoplasias include sustained proliferation, resistance to apoptosis, evasion of growth suppression, angiogenesis, tissue invasion, and, in many cases, metastatic spread. Not all tumors follow the same course; some malignant neoplasias can be aggressive, others indolent, and some remain in situ.

Classification: benign neoplasias include lipomas, adenomas, fibromas, and hemangiomas, which are typically well circumscribed. Malignant neoplasias include carcinomas (epithelial origin), sarcomas (mesenchymal), leukemias, lymphomas, and gliomas, among others. Some tumors are designated as carcinoma in situ or intraepithelial neoplasia, indicating a premalignant or noninvasive stage.

Diagnosis and treatment: diagnosis often involves clinical assessment, imaging, and histopathology from biopsy or surgical specimens. Treatment depends on type, stage, and patient factors, and may include surgery, radiation therapy, chemotherapy, hormonal therapy, targeted therapy, or immunotherapy. Prognosis varies widely and is influenced by tumor type, stage at diagnosis, and response to treatment.