hyalinized

Hyalinized is an adjective used in pathology to describe tissue that has undergone hyalinization, a change in which extracellular material becomes glassy, eosinophilic, and homogenous on light microscopy. The term hyaline comes from a Greek word meaning glassy or transparent, and hyalinization refers to the transformation or deposition of proteinaceous material that yields a characteristic pink, refractile appearance on routine stains.

Histologically, hyaline material is typically eosinophilic and intensely homogenous. In blood vessels, hyalinization often manifests as hyaline arteriolosclerosis, with thickened vessel walls due to deposition of plasma proteins and extracellular matrix. In the kidneys, hyaline changes can accompany diabetic microangiopathy and lead to nodular glomerulosclerosis (Kimmelstiel-Wilson lesions) in which hyaline deposits affect arterioles and mesangial areas. In other tissues, hyalinization may occur in the stroma of tumors or in aging connective tissue, producing hyaline or glassy-looking areas within otherwise normal or fibrous tissue.

Hyalinized tissue must be distinguished from other glassy deposits. Amyloid, for example, is hyaline in appearance but shows Congo red positivity with apple-green birefringence under polarized light, whereas hyaline material in hyalinization is non-amyloid. Collagen deposition can also create thickened, eosinophilic areas, which may be differentiated with special stains such as Masson’s trichrome.

In summary, hyalinized describes tissue that has developed hyaline change—glassy, eosinophilic material that alters tissue architecture and is commonly seen in chronic vascular or degenerative contexts, as well as in certain tumor stromal processes.