Metaplasiaan

Metaplasiaan, or metaplasia, is a process in which mature, differentiated cells in a tissue are replaced by another mature cell type. It is usually an adaptive response to chronic irritation, inflammation, or injury. Unlike dysplasia or neoplasia, metaplasia is not itself cancer, and the change can be reversible if the inciting stimulus is removed. In Dutch medical terminology, the term for this process is metaplasiaan.

Common forms of metaplasia include squamous metaplasia, where glandular or columnar epithelium becomes stratified squamous epithelium. This is frequently seen in the bronchial mucosa of smokers or in chronically irritated airways. Intestinal, or glandular, metaplasia occurs when mucosa adopts an intestinal-type epithelium with goblet cells, as seen in Barrett’s esophagus in response to chronic gastroesophageal reflux. Intestinal metaplasia can also occur in the stomach with chronic gastritis. Osseous or cartilaginous metaplasia refers to bone or cartilage formation in soft tissues and may arise after prolonged inflammation or injury.

Mechanistically, metaplasia involves shifts in gene expression and cell identity programs driven by environmental cues and signaling pathways that reprogram differentiation. It is often reversible if the original stress is removed, but persistent metaplasia can increase the risk of dysplasia and, in some contexts, cancer, as observed in Barrett’s esophagus.

Diagnosis is typically made by histopathological examination of biopsy samples. Treatment focuses on eliminating the underlying irritant and monitoring for complications. In Barrett’s esophagus, endoscopic surveillance is used due to the associated cancer risk.