Fig. 2

Muscle biopsy specimen on light microscopy. Hematoxylin and eosin staining (a) shows a small cluster of atrophic angulated fibers and mild fiber size variation. Modified Gomori trichrome stain (b) shows tiny inclusions in fibers (white arrowheads). Congo red staining (c) shows amyloid proteins in which birefringence is observed under the polarizing microscope (d) and which is positive under the fluorescence microscope (e) in the sarcolemma and blood vessel walls (white arrowheads)