Nose, Epithelium - Hyperplasia
comment:Transitional or respiratory epithelial hyperplasia is a relatively common treatment-related change and can also be seen in inflammatory lesions caused by foreign bodies and infectious agents. Hyperplasia is an increase in the number of cells and should not be confused with regeneration, which is replacement of lost or damaged cells. Hyperplasia results in thickening of the epithelium ( Figure 2 , Figure 3 , and Figure 6 ) and may result in cellular crowding that forces the epithelium into folds ( Figure 2 and Figure 3 ). However, the mucosal surface of the caudoventral nasoturbinate is normally folded; this should not be interpreted as respiratory epithelial hyperplasia. Mucosal invaginations of hyperplastic epithelium ( Figure 4 and Figure 5 ) may extend into the lamina propria and may contain some inflammatory cells or concretions. Invagination of hyperplastic epithelium is thought to occur with prolonged hyperplasia. Goblet cell proliferation ( Figure 6 ) is a common response of the epithelium and is often seen concurrently with hyperplasia. Hyperplasia of the olfactory epithelium typically results in thickening of the epithelial layer ( Figure 7 ).
recommendation:Hyperplasia of the transitional or respiratory epithelium should be diagnosed whenever present and assigned a severity grade. The site listed in the diagnosis should reflect the epithelial cell type affected. If a particular cell type can be identified as the proliferating cell (e.g., basal cell or goblet cell), that cell type should be included as a modifier. Since these cells are proliferating, they are often slightly larger (hypertrophy) than nonproliferating respiratory epithelial cells. Hypertrophy should be diagnosed separately only if the pathologist is confident that the enlargement is beyond that expected for proliferating cells. If the epithelial cells appear to be abnormal (e.g., cellular or nuclear pleomorphism, anaplasia, or enlargement) or there is an abnormal or aberrant growth pattern (e.g., disorganization of the cells, dyskeratosis, or increased or abnormal mitotic figures), the term “atypical” should be added as a diagnostic modifier (see Nose, Epithelium - Hyperplasia, Atypical). Regenerating epithelial cells may have some irregularity in their cytologic features and arrangement; care must be taken not to mistake this for atypical hyperplasia.
related links:Nose, Epithelium - Hyperplasia, Atypical
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Web page last updated on: February 24, 2015