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

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) and systemic (PFS) 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 was ∼15 years (10-year PFS 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.