Secondary bladder amyloidosis with familial Mediterranean fever in a living donor kidney transplant recipient: a case report

BACKGROUND: Secondary bladder amyloidosis is an extremely rare disease, resulting from a chronic systematic inflammatory disorder associated with amyloid deposits. Although uncommon in Japan, familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease characterized by recurrent episodes of fever of short duration and serositis and is frequently associated with systemic amyloidosis. Here, we present a case of a Japanese patient complaining of fever and macroscopic hematuria after a living donor renal transplantation. Consequently, he was diagnosed with secondary bladder amyloidosis with FMF. CASE PRESENTATION: A 64-year-old Japanese male received a living ABO-incompatible kidney transplant from his wife. The postoperative clinical course was normal, and the patient was discharged 21 days after the transplantation with a serum creatinine level of 0.78 mg/dl. The patient frequently complained of general fatigue and fever of unknown origin. Six months later, the patient presented with continuous general fatigue, macroscopic hematuria, and fever. Cystoscopic examination of the bladder showed an edematous region with bleeding, and a transurethral biopsy revealed amyloid deposits. His wife stated that the patient had a recurrent high fever since the age of 40 years and that his younger brother was suspected to have a familial autoinflammatory syndrome; thus, the patient was also suspected to have a familial autoinflammatory syndrome. Based on his brother’s medical history and the genetic tests, which showed a homozygous mutation (M694V/M694V) for the Mediterranean fever protein, he was diagnosed with FMF. Although colchicine treatment for FMF was planned, the patient had an untimely death due to heart failure. We re-evaluated the pathological findings of the various tissue biopsies obtained during the treatment after the renal transplantation. Immunohistochemistry revealed amyloid deposits in the bladder region, renal allograft, and myocardium and the condition was diagnosed as AA amyloidosis associated with FMF. CONCLUSION: We presented a case of systemic amyloidosis with FMF, involving the bladder region, myocardium, and renal allograft, diagnosed after renal transplantation. Bladder amyloidosis should be considered in patients with macroscopic hematuria, particularly in the kidney transplant recipients with idiopathic chronic renal disease. Diagnosis of secondary bladder amyloidosis may result in the early detection of underlying diseases, which may contribute to patient prognosis.