Colovesical Fistula and Amyloidosis.

Systemic amyloidosis results from an abnormal deposition of toxic insoluble beta-sheet fibrillar protein in extracellular tissues, causing damage to multiple organ systems. Amyloid proteins (e.g., transthyretin, light chains, and serum amyloid A) may infiltrate the mucosa or vascular structures, resulting in gastrointestinal manifestations, including bleeding and diarrhoea. We discuss a case of a 71-year-old male with systemic immunoglobulin G kappa amyloid light chain amyloidosis who developed a colovesical fistula related to amyloid deposition.