Members of the DEWS Definition and Classification. Subcommittee developed a contemporary definition of dry eye disease and a three-. part classification system based on etiology, causative mechanisms and disease. severity.
Metaplasia. Definition: Metaplasia is the reversible replacement of one differentiated cell type with another differentiated cell type. Metaplasia causes precursor cells to change their cell fate, and do not change existing differentiated cells.he most common epithelial metaplasia is columnar to squamous (squamous metaplasia), as occurs in the respiratory tract in response to chronic irritation.
âAtypicalâ features of flat epithelial hyperplasia. When a neoplasm (an unexpected growth of new cells) is described as â atypical â, that tends to be a bit more worrisome in terms of whether or not the hyperplasia is associated with breast cancer.ometimes this neoplasm is called â columnar cell hyperplasia â due to the architecture of the growth pattern. It tends to grow in a â flat â pattern, without any strange build-ups or unevenness, and tends to grow into â columns â; growing taller without growing wider.