Presentation and Outcomes of Localized Immunoglobulin Light Chain Amyloidosis: 14-Year Experience of an Academic...

Localized light chain amyloidosis (loc-AL) is a rare disorder characterized by localized deposition of misfolded AL fibrils. There are limited data on patterns of disease presentation and long-term outcomes. In this study, we retrospectively reviewed 146 patients with loc-AL at our institution between January 1, 2010, and March 1, 2024. We excluded patients with evidence of systemic AL amyloidosis. We calculated local (PFS_L) and systemic (PFS_s) progression free survival (PFS) and overall survival (OS) using the Kaplan-Meier method. We found that loc-AL most commonly involved the respiratory (26%), gastrointestinal (17%), head and neck (17%) and genitourinary (10%) systems. Overall, 51% patients were asymptomatic at presentation, and 16% had a co-existent autoimmune disease. First line management included observation (52%), surgical resection (39%), chemotherapy (3%), and radiation (2%). Most patients (59%) had a response with first-line therapy. The median PFS_L was ∼15 years (10-year PFS_L 68%), and median OS was not reached (10-year OS 83%). None of the patients had progression to systemic amyloidosis. Seventeen patients had local recurrence and required second line therapy. In conclusion, loc-AL has an excellent prognosis and does not progress to systemic AL amyloidosis. Observation and/or surgical removal are usually adequate first-line approaches; however, a small proportion of patients can relapse locally requiring repeated interventions for symptom control.