|Hyaline - Value of a descriptive word in
General Pathology and Dermatopathology
Dr Sampurna Roy MD May 2016
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Hyaline is a descriptive term applied to any homogeneous eosinophilic material.
Literally, the term means "glassy" derived from the Greek word "hyalinos", and is commonly applied to changes in connective tissue.
For more than a century pathologists and dermatopathologist have repeatedly used this term in various conditions.
What exactly is a hyaline change?
Hyaline change or degeneration is used to describe a change in cells when either the whole cell or part of it becomes eosinophilic and homogeneous.
Probably several processes are included, but in the hyalinization of the collagen the material appears very uniform.
One should understand that the term is merely descriptive of a particular microscopic appearance.
A wide range of conditions have been included in General Pathology and Dermatopathology
To the alcoholic patient the cells of the liver sometimes contain eosinophilic structures called "Mallory bodies", or "alcoholic hyaline".
The material consists of a meshwork of fibrils in an area where the rough endoplasmic reticulum has broken up.
The droplets that appear in the proximal convoluted tubular cells of the kidney in the nephrotic syndrome are due to the excessive reabsorption of protein which has leaked through an abnormal glomerulus.
The condition is similar to the effects of an intravenous sucrose injection, when droplets appear in the tubular cells.
In "hyaline droplet degeneration" of the kidney, there may be associated degenerative changes with the formation of large cytolysomes.
Most of the droplets seen on light microscopy consist of reabsorbed protein, and the condition is not really a degeneration.
Glomeruli of chronic nephritis are converted into hyalinised, eosinophilic balls.
These usually have two components.
The remains of the glomerulus is represented by a mass of basement-membrane-like substance (which is PAS-positive), and the second component is hyalinised collagen produced by the parietal cells of Bowman’s capsule.
In Hematoxylin and Eosin sections the two components cannot be easily distinguished.
Deposits of hyaline material may also replace epithelial cells.
In Cushing' disease, ACTH producing adenoma of the pituitary show Crooke's Hyalinization.
Pancreas: A good example is the hyalinsation of the islets of Langerhans that is sometimes seen in diabetes mellitus.
Apparently the substance is laid down around the sinusoids, and eventually replace the glandular structure.
This type of hyaline is a type of amyloid.
"Amyloid may be considered as a type of hyaline material, but because of its special properties it is considered separately."
Uterus: Fibroid tumours of the uterus (leiomyomata).
The appearance of homogeneous hyaline material in the subendothelial layer of arterioles is common event, and in the spleen of adults may be regarded as normal.
In the afferent arterioles of the renal glomeruli it is associated with benign systemic hypertension and diabetes mellitus.
The nature of this hyaline has been much debated. According to some authors it is perhaps fibrin, derived from the blood.
It has been claimed that fibrin, as it ages, becomes transformed into an acellular substance which has staining properties of collagen.
Other possibilities are that vascular hyaline is derived from smooth muscle or collagen, or that it consists of basement-membrane-like substance.
Castleman's disease- Vascular-Hyaline Type.
1) Lipoid proteinosis also known as Hyalinosis cutis et mucosae :
(Visit: Lipoid Proteinosis)
PAS-positive diastase resistant hyaline material is demonstrated around small blood vessels and at the periphery of eccrine sweat glands.
Thick PAS positive hyaline bands surround tumour islands.Hyaline droplets may be present within the nests.
3) Kaposi's Sarcoma:
(Visit: Pathology of Kaposi's sarcoma)
Periodic acid-Schiff-positive, diastase-resistant, eosinophilic hyaline globules representing degenerating erythrocytes are found within cells of the plaque and nodular stages
4) Erythema Elevatum Diutinum
There is widespread vasculitis and fibrin deposits (toxic hyalin) are noted within and around the walls of the small dermal vessel together with endothelial swelling.
5) Spitz Nevus:
(Visit: Pathology of Spitz Nevus )
Collection of pale eosinophilic, periodic acid-Schiff-positive hyaline globules (Kamino bodies) at the epidermodermal interface.
The histological appearances of keloids are characterized by a nodular fibroblastic proliferation and the presence of hypocellular, glassy , eosinophilic, hyalinized collagen fibers in the dermis.”
7) Waldenstrom's Macroglobulinemia
Hyaline deposits fill the papillary and reticular dermis. The deposits are PAS positive.
8) Colloid Milium
Visit: Pathology of Colloid Milium
9) Pleomorphic Hyalinizing Angiectatic Tumour
10) Juvenile hyaline fibromatosis
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