Bladder, ureter & renal pelvis

Other nonneoplastic


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Last staff update: 23 November 2020

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PubMed Search: Bladder amyloidosis

Alcides Chaux, M.D.
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Cite this page: Chaux A. Amyloidosis. website. Accessed October 4th, 2023.
Definition / general
  • Deposition of amyloid protein in urinary bladder
  • Almost always primary (amyloid tumor); rarely part of systemic disease
  • Preferentially affects posterior and posterolateral walls
  • Can be primary (AL type amyloid), secondary (AA type amyloid) or familial (ATTR type amyloid)
  • Systemic secondary bladder amyloidosis is associated with autoimmune disease and chronic infection
  • Familial cases are associated mostly with mutations in the transthyretin gene

Clinical features
  • Transurethral resection and fulguration of amyloid tumor is usually curative, since not associated with myeloma (Am J Surg Pathol 1978;2:141); also controls bleeding
  • Partial cystectomy for large, mass forming lesions
Microscopic (histologic) description
  • Large masses of eosinophilic proteinaceous material with hemorrhage in lamina propria
  • Variable foreign body giant cell reaction to amyloid
  • May have associated atypical epithelium due to attenuation of urothelium
  • Rarely perivascular amyloid deposits, especially in systemic amyloidosis
  • Rare / no inflammatory cells
Positive stains
  • Congo red shows apple green birefringence when exposed to polarized light
  • Amyloid panel (kappa and lambda light chains, prealbumin, beta-2-microglobulin, SAA1)
  • Immunofluorescence with Thioflavin T
Electron microscopy description
  • Nonbranching, randomly distributed, rigid fibrils (8 - 10 nm) and associated ground substance
Differential diagnosis
  • Fibrosis: positive for trichrome stain, negative for Congo Red, no Thioflavin T immunofluorescence
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