Gallbladder amyloidosis is often unexpected and may have systemic implications.

Abstract

The aim of this study was to evaluate a large cohort of gallbladder amyloid cases to determine clinical and morphologic features. Cholecystectomy specimens (N = 118) typed using proteomics-based techniques between 2008 and 2023 were identified. Clinical and morphologic features were reviewed. Six amyloid types were identified: ATTR (n = 63, 53.4%), AL (n = 46, 39.0%), AA (n = 4, 3.4%), AApoA1 (n = 2, 1.7%), ALECT2 (n = 2, 1.7%), and AEFEMP1 (n = 1, 0.8%). Amyloidogenic mutations were detected in 3 ATTR cases and 2 AApoA1 cases. Morphologic review (n = 26) revealed perimuscular vessel involvement in all cases. Amyloidosis was an unexpected diagnosis first made on the cholecystectomy specimen in half of the patients with clinical information (n = 10). All 9 patients with follow-up had evidence of systemic disease. In 2 patients, cholecystic involvement was initially missed and only retrospectively identified after the diagnosis of cardiac amyloidosis. In patients with clinical data, amyloidosis was often unexpected, the gallbladder was commonly the first tissue sampled with amyloidosis, and all patients had systemic disease. Thorough review of cholecystectomy specimens with careful inspection of perimuscular vessels, coupled with a low threshold for ordering Congo red stain in elderly individuals and amyloid typing using a robust method such as proteomics, can prevent a delay in amyloid diagnosis and management.