Cardiac Amyloidosis - XI
Incidental amyloid in a calcified aortic valve. A. Light micrograph of an aortic valve with marked calcification. There is abundant fibrosis and several cores of basophilic deposits corresponding to areas of calcified extracellular matrix. At this low magnification, there is no overt “amorphous” amyloid deposition identified. (H&E X100). B. The rectangular highlighted portion of the valve in image A shows a close up of the extracellular matrix and calcium deposits but no overt amyloid deposits. (H&E, X300). C. The same area of the valve is shown in as a bright field micrograph stained with Congo Red. A small focus of the matrix is stained red (“congophilic”). The calcium deposits are basophilic. (Congo red, X300). D. Examination of the same field under polarized light microscopy shows the extracellular matrix of collagen as birefringent white matrix. In contrast, the small area of “congophilic” material show apple green birefringence under the polarized visible light. (Congo Red, X300). E. At higher magnification, the “congophilic” area of the extracellular matrix of the valve stands out in bright field microscopy. (Congo red, X900). F. Polarized light microscopy shows distinct “apple green” birefringence of the congophilic deposits. (Congo red, X900).
Ultraviolet light microscopy of the Congo Red positive deposit in the valve is autofluorescent when analyzed with: G. Ttetramethylrhodamine isothiocyanate (TRITC) filter (Congo red X900). H. A 4',6-diamidino-2-phenylindole (DAPI) filter (Congo red X900). I. A Fluorescein isothiocyanate (FITC) filter (Congo red X900).
Incidental findings in cardiac amyloidosis may include foreign body giant cell reaction.