S5826 Sinusoidal Amyloidosis in the Setting of Acute Rejection: A Rare Finding in a Long-Term Liver Transplant Recipient

Introduction: Amyloidosis is a heterogeneous group of diseases characterized by extracellular deposition of insoluble protein fibrils which can disrupt the architecture and function of vital organs. While systemic amyloidosis is well documented, its emergence following solid organ transplantation, particularly liver transplantation, is rare and poorly characterized. Case Description/Methods: A 54-year-old woman with a history of deceased donor liver transplant (DDLT) in 1999 secondary to Alagille syndrome, end-stage renal disease on hemodialysis, and hypertension presented with hematemesis after dialysis. She had previously been adherent to her immunosuppression for 9 years before discontinuing due to socioeconomic constraints, leading to a 14-year lapse in care. Labs notable for hemoglobin: 8.7 g/dL, platelets: 130 K/mcL, international normalized ratio: 1.1, albumin: 2.1 g/dL, T bilirubin: 1.4 mg/dL, alkaline phosphatase 251 U/L, ALT: 62 U/L, and aspartate aminotransferase: 88 U/L. Upper endoscopy revealed erosions and a visible gastric fundus vessel that was clipped. MRCP showed biliary anastomotic narrowing with upstream extrahepatic/intrahepatic biliary dilation, leading to ERCP with stent placement. Concerned for chronic graft rejection, she underwent liver biopsy showing moderate T-cell mediated rejection (rejection activity index 5/9), no advanced fibrosis, and positive Congo Red staining for sinusoidal amyloid deposition. Shortly thereafter she stabilized and was discharged with outpatient follow up. Discussion: De novo development of amyloidosis in liver transplant (LT) recipients is rare, though both acquired and hereditary forms have been reported. The DDLT occurred years earlier at an outside facility, with limited donor information but noted prior good health. Our patient had no known polyneuropathy or cardiomyopathy, typically seen in familial and wild-type transthyretin amyloidosis respectively. Her case likely reflects new-onset amyloidosis developing post-transplant. Although amyloid deposition typically does not cause acute rejection, buildup could indirectly mimic or worsen graft function. Chronic inflammation, immune dysregulation, and organ damage from rejection or infection may contribute to secondary amyloid deposition. This case underscores the complexity of post-LT care in patients with poor follow-up and highlights the importance of considering amyloidosis in atypical presentations. Moreover, it raises questions about whether long-standing allograft inflammation could contribute to amyloidogenesis in susceptible individuals.