Bladder & urothelial tract
Other nonneoplastic
Amyloidosis
Author: Alcides Chaux, M.D.
Last author update: 1 March 2011
Last staff update: 23 November 2020
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Bladder amyloidosis
Table of Contents
Definition / general | Sites | Etiology | Clinical features | Treatment | Microscopic (histologic) description | Positive stains | Electron microscopy description | Differential diagnosisCite this page: Chaux A. Amyloidosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladderamyloidosis.html. Accessed April 25th, 2024.
Definition / general
- Deposition of amyloid protein in urinary bladder
- Almost always primary (amyloid tumor); rarely part of systemic disease
Sites
- Preferentially affects posterior and posterolateral walls
Etiology
Systemic
Localized
- 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
Localized
- Unknown etiology
- Mostly AL type amyloid (immunoglobulin light chains, Urology 2006;67:904)
Clinical features
- Patients present with gross, painless hematuria (Mayo Clin Proc 2000 75:1264)
- May clinically resemble bladder cancer (Indian J Pathol Microbiol 2008;51:415)
- Urinary dysfunction found in 50% with familial amyloidotic polyneuropathy (Neurourol Urodyn 2009;28:26)
- Primary amyloidosis has a high rate of local recurrence
- Prognosis of secondary amyloidosis depends on primary cause
Treatment
- 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
