Classification of amyloidosis

1. According to the cause:

a) primary (idiopathic), b) hereditary (genetic, family), c) secondary (acquired), d) senile.

2. According to the propagation: a) generalized, b) localized.

3. According to the involved organ:

a) cardiopathic, b) nephropathic, c) neuropathic, d) hepatopathic, e) epinephropathic, f) mixed type, g) APUD amyloidosis.

4. According to the type of amyloid fibril protein: AL (amyloid light chain), AA (amyloid associated), AE (amyloid endocrine), AS (amyloid senile).

Amyloid light chain (AL) — is made of immunoglobulin light chain, usually X and less often k.

Amyloid associated (AA) consists of serum amyloid associated, an acute-phase reactant that is the apoprotein of a high density lipoprotein.

Amyloid endocrine (AE) — is a hormonal polypeptide.

Amyloid senile (AS) — is related to prealbumin.

Amyloid formation may be connected with collagen or reticular fibers. In the first case amyloidosis is called pericollagen. Amyloid is accumulated along

the collateral fibers thus invading adventitia of small and middle-sized vessels, myocardium, skin, etc. In perireticular amyloidosis amyloid is accumulated along the basal membranes of the vessels, glands as well as reticular network of parenchymatous organs (liver, kidneys, spleen, adrenal glands). Macroscopic examination reveals enlarged, dense organs. They are fragile on incision and have sebaceous appearance. The spleen may be sago-like and sebaceous. In the kidneys, amyloid accumulates in the walls of the vessels, capillary loops and glomerular mesangium, in tubular basal membrane, along reticular and collateral fibers of the stroma. The outcome is kidney wrinkling resulting from connective tissue growth.

In the liver amyloid accumulates among stellate reticuloendotheliocytes, reticular tissue of the lobules, in the walls of the vessels, ducts and connective tissue. In the adrenal glands, bilateral lesion along the vessels and capillaries is observed. In the heart amyloid accumulates under the endocardium, in the stroma, myocardial vessels, along the veins in the epicardium. It results in cardiomegaly. In the lungs it accumulates in the walls of pulmonary arteries and veins, in peribronchial connective tissue, in interalveolar septa, in the brain (senile amyloidosis) in the vessels, brain membranes and senile plaques of the cortex, in the pancreas in the arteries, islands of Langerhans. A part from that, amyloid accumulates in the tumors of endocrine and APUD system. As a rule amyloid is

often discovered in the stroma of thyroid cancer, pheochromocytoma, hypophyseal adenoma, hyper-nephroid renal cancer, etc.

The outcome is unfavorable. Amyloidoclasia (resolving of amyloid by macrophages) is rare. As a rule parenchyma atrophy, sclerosis (with resultant hepatic, renal, cardiac, pulmonary, adrenal insufficiency and the death of the patient) develop in the involved organs.

Stages of individual work in classStudy and describe macrospecimens

Fatty accumulation of the myocardium (tigers heart). Pay attention to the organ size, expansion of the chambers, soft texture. Characterise the appearance of the sectioned myocardium, pay attention to the greenish-yellow colour. Describe the appearance from the endocardial side. What is related to the yellowish-white striations from the endocardial side, especially deeply expressed in muscles and trabecules of the heart ventricles?

Steatosis (goose's liver). Pay attention to the organ size, flabby texture, yellowish-ochre colour of the parenchyma. What is the cause of such changes? What are possible outcomes?

Large white kidney — lipid accumulation of the kidney. Pay attention to the organ size, flabby texture and white colour of the parenchyma. How do you characterise the type of the sectioned tissue? What are the causes of such changes? What are possible outcomes?

Spleen in Gaucher s disease: Describe the appearance of the macrospecimen. Pay attention to the organ enlargement, changes in colour, texture. What are the causes of the changes in the appearance of the organ in Gaucher's disease? Pay attention to the nodular and diffuse nature of cerebrosid deposition.

Hyalinosis of the spleen capsule (glased spleen, suga-ricing spleen). Describe spleen capsule, colour, texture and outlook. Characterise the nature of capsule changing. Give the definition of the process, indicate previous condition. Characterise the level of reversibility.

Amyloidosis of the spleen (sago spleen). Describe the dimensions of the organ, its texture, colour, appearance on the section. Indicate the nature of process, localisation of amyloid. Define the process, indicate the steps of morphogenesis. Name specific microscopic staining for amyloid.

Amyloidosis of the spleen (sebaceous or waxy spleen). Describe the dimensions of the organ, its texture, colour, appearance on the section. Indicate localisation of amyloid. Indicate the difference between «sebaceous» and «sago» spleen.

Amyloidosis of the kidney. Describe the dimensions of the organ, its texture, the width of cortical layer, the appearance of surface on the section. Name the diseases which can outcome to amyloidosis of kidney. What is the result of it?

Obesity of the hart. Determine the dimensions of the organ. Pay attention to the quality of fat under the epicardium. Pay attention the growth of fatty tissue in the heart wall on the section, more developed in the right portions. Characterise the type of dysfunctional fatty metabolism. Name the etiology and mechanisms of development of the general obesity, its significance, outcome.

Atherosclerosis of the aorta. Characterize the appearance, colour of the aortic intima. Define the nature of the changes, explain the mechanism of development, significance for the organism.