Clinical History: 68 year-old male with 5
year history of restrictive cardiomyopathy, who had multiple episodes of
syncope. His kappa: lambda free L/C ratio was found to be 0.42 (n 0.58-2.24).
Histology: A heart biopsy was performed and H&E sections
(Figures A & B) show myocardial tissue with
unremarkable cardiomyocytes and mild to moderate interstitial fibrosis, confirmed by trichrome staining
(Figures C and D). The small vessels show moderate wall thickening with
accumulation of smudgy, light eosinophilic material with cracking appearance,
which stains light purple with the trichrome staining. Congo red staining (Figure E) viewed under
polarized light shows apple-green birefringence consistent with amyloid
deposits. Electron microscopic examination (Figures F and G) reveal
cardiomyocytes and vascular structures surrounded by a fibrillary material
(Figure G) consistent in size and appearance with amyloid (n 5-15
nanometer). |