Electron microscopic characteristics of beta2-microglobulin amyloid deposits in long-term haemodialysis.

The electron microscopic features of beta2-microglobulin amyloid, deposited in the synovial membrane, are presented and discussed. The patient, a 69-year-old woman underwent chronic hemodialysis for 3 years. Because of constant pain and destructive arthropathy, endoprosthesis of the hip joints were implanted. Extra- and intracellular filamentous-fibrillar amyloid deposits have been demonstrated in ultrathin sections. The extracellular amyloid deposits showed a loose, filamentous or fibrillar structure at the periphery and a dense central core. The loose, filamentous structure may represent an early stage of fresh, newly deposited beta2-microglobulin amyloid, while the condensed and fragmented amyloid filaments may be an advanced "mature" stage of amyloid deposition.