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Systemic AA amyloidosis is a rare complication of benign tumours. This report describes a patient with hepatocellular adenoma associated with reactive AA amyloidosis. He had a nephrotic syndrome with deteriorating renal function and an increase of serum concentrations of acute phase proteins, mainly C-reactive protein. Resection of the tumour was followed by improvement in renal function and a marked decrease of the serum concentrations of acute phase proteins.

The beta-2 microglobulin type of amyloidosis was identified in articular and para-articular tissues of 14 patients with non-amyloid nephropathies undergoing long-term hemodialysis. Ten patients had carpal tunnel syndrome, 13 had juxta-articular radiolucent cysts (complicated by spontaneous fractures of the femoral neck in three), and six had destructive arthropathies of the large joints of the limbs. Massive amyloid deposits were found in the synovium, capsule, ligaments, articular cartilage, and/or bone. They were characterized by Congo red-induced green birefringence that was sensitive to potassium permanganate treatment. They reacted with anti-beta-2 microglobulin antiserum, whereas they did not react with antibodies directed against AA protein, prealbumin, or immunoglobulins. These data suggest that the potentially disabling arthropathy of hemodialysis is due to amyloid lesions. The persistently elevated plasma beta-2 microglobulin levels may play a role in the pathogenesis of this recently recognized complication, and if so, this complication should be preventable.

Forty-five renal biopsies with amyloidosis were studied by light microscopy with Congo red staining and action of potassium permanganate and by immunofluorescence with antihuman tissue A component antiserum antilight and heavy chains of immunoglobulins antisera. The patients were classified on the basis of concordance between immunohistochemical characterization by immunofluorescence and the results of Congo red staining after potassium permanganate treatment. Thus, 37 of 45 cases (82%) were classified by immunohistochemical characterization (15 with AL amyloidosis and 22 with AA amyloidosis) when the amyloid type could be hypothetized in only 31 of these cases (66%) on the basis of clinical criteria. This study suggests that the association of these two technics is more reliable than clinical data alone in distinguishing between AA and AL amyloidosis.

We studied 56 patients who had been receiving peritoneal dialysis for greater than 3 years, to investigate the prevalence of rheumatic diseases suggestive of beta 2-microglobulin (beta 2m) amyloid deposition. Eight patients were found to have carpal tunnel syndrome, 16 had chronic shoulder pain, 8 had subchondral bone cysts, and 13 had destructive arthropathies. Amyloid reacting with anti-beta 2m was demonstrated in the hip synovium of 1 patient. Serum beta 2m levels were elevated in all patients. These data suggest that peritoneal dialysis, like hemodialysis, may lead to the development of an arthropathy associated with beta 2m accumulation and beta 2m amyloid deposition.