Associated with multiple myeloma or macroglobulinemia. Other rare familial types. May not be visible grossly if primarily distributed in the walls of small blood vessels, or in early minimal deposition in any organ. Advanced cases involving the heart, liver, spleen, or kidneys have a light tan yellow discoloration, with a characteristic stiff wax-like consistency. This is due to the extensive replacement of the tissues by amyloid with enlargement of the organs.
Advanced cases result in replacement of parenchyma by pressure atrophy with associated organomegaly.
Uptake of congo red stain with green fluorescence under polarized light considered pathognomonic. Varies with different types. Cases with AA and AL types may develop heart failure, liver failure, or nephrotic syndromes with later renal failure. AB and AScr types are components of lesions of Alzheimer's disease, and Creutzfeld Jakob disease, respectively. All organs may be involved.