IPLab:Lab 6:Senile Amyloidosis

Clinical Summary

This 87-year-old black male diabetic was admitted for amputation of the lower extremity involved by atherosclerotic gangrene and osteomyelitis. Following amputation, the patient's course was one of progressive deterioration. Laboratory studies immediately prior to death revealed a blood glucose of 840 mg/dL and a serum CO2 (bicarbonate) of 8.5 mmol/L.

Autopsy Findings

The heart weighed 540 grams. The endocardial surface of both atria presented a mottled gray-red and gray-white appearance. Multiple sections through the myocardium revealed a marked 'pallor' of the muscle.

Images

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  This is a gross photograph of section of heart tissue from this case. The tissue was firm and had a waxy texture. If you use your imagination you can see pale yellow areas within this tissue which represent the amyloid deposits.

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  This is a low power photomicrograph of the heart tissue from this case. At this magnification the structure looks relatively normal.

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  This is a higher-power photomicrograph of the heart tissue from this case. Note the amyloid deposition throughout the myocardium (1) as well as deposition in the wall of the blood vessel (2).

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  This is a higher-power photomicrograph of extracellular amyloid (1) and deposition of amyloid in the vessel wall (2).

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  This is a special stain for amyloid (Luxol PAS) demonstrating the amyloid (1) and fibrosis (2) in the myocardium. The amyloid is darker purple/magenta and tends to be more amorphous. The fibrosis is pink and more fibrillar.

Study Questions

• What protein makes-up senile amyloid in the ventricle of the heart?

Transthyretin.

• What protein makes-up senile amyloid in the atrium of the heart?

Atrial natriuretic peptide.

• At what age does senile amyloidosis usually develop?

Eighth and ninth decades.

• Where else may senile amyloid deposits occur?

Senile amyloid deposits also occur in the lungs, pancreas, and spleen. Senile cerebral amyloidosis occurs due to deposition of A beta 2 protein in cerebral blood vessels and in senile plaques of Alzheimer's disease patients.