Acquired non-neoplastic anomalies

Author: Alcides Chaux, M.D. (see Authors page)

Revised: 21 March 2016, last major update March 2011

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Bladder amyloidosis
Cite this page: Amyloidosis. website. Accessed October 25th, 2016.
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

  • Unknown etiology
  • Mostly AL-type amyloid (immunoglobulin light chains, Urology 2006;67:904)
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
Micro 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
Micro Images

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Laryngeal amyloidosis

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Subepicardial deposition of amyloid
(Congo red stain with polarizing microscopy)

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
  • Non-branching, 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