Rarely occurs in the bladder and is more often a primary localized process than a reflection of systemic amyloidosis.
Primary amyloidosis is due to AL-type amyloid.
Secondary amyloidosis is associated with hemodialysis, multiple myeloma, autoimmune causes and chronic infections.
Age: Typically in adults (5th and 6th decades) and presents with hematuria.
Localized amyloidosis may present as a solitary "tumor" mass that ulcerate the mucosa and masquerade as a malignancy.
Gross: Diffuse amyloidosis can be visualized as mucosal erythema.
Deposition of eosinophilic amorphous materials in lamina propria and muscularis propria, with associated histiocytic and foreign body giant cell reactions (image A).
Vessel wall may also appear thickened by amyloid deposits, usually in systemic amyloidosis.
Congo red stain shows dense orange-brown under light microscopy and apple green birefringence under polarized light (image B), confirming the diagnosis.
Electron microcopy shows nonbranching rigid 8-12 nm fibrils.
Immunohistochemistry for typing (e.g. κ or λ light chains)
Localized bladder amyloidosis has high recurrence rate of ~50%.