Amyloid

Pathological proteinaceous substance deposited extracellularly. May encroach on cells and produce pressure atrophy.

Identification

Histologically

  1. amorphous, hyaline
  2. pink-red, eosinophilic

Congo Red stain: Apple-green, birefringent.

Composed of stacked beta-sheets. Derived from many different proteins, but all have this common structure.

Classification (Clinical)

Type of amyloid in brackets ().

AL = amyloid light chain
AA = amyloid assiciated [protein]
ATTR = amyloid transthyretin
ACal = amyloid procalcitonin
AIAPP = amyloid islet associated polypeptide

Presentation

May be clinically silent.

Proteinuria, macroglossa.