Presentation and Outcomes of Localized Immunoglobulin Light Chain Amyloidosis: The Mayo Clinic Experience

To describe treatment types, outcomes, and relapse patterns in patients with localized immunoglobulin light chain amyloidosis (AL_L).

We included all patients with AL_L seen at Mayo Clinic in Rochester, Minnesota, from January 1, 1968, through June 30, 2014. The diagnosis of AL_L was predicated on the presence of a Congo red-positive biopsy specimen and negative serum and urine immunofixation. Treatment response categories were response, stability, and progression. Localized and systemic progressions were defined as progression of disease at the site of origin or appearance of clonal plasma cells in a bone marrow biopsy sample, respectively.

Of 5551 patients with AL, 413 (7%) had AL_L. The most common site involved was urothelial tissue (n=85, 21%), followed by the larynx (n=57, 14%). Coexisting autoimmune diseases were reported in 7% of patients (n=28). The most common first-line treatment was excision of the amyloid deposits (61%), followed by observation or supportive care (28%). When considering symptomatic patients only (n=284), 205 (72%) improved, 23 (8%) had stable disease, and 55 (19%) could not be evaluated for response. Ten-year survival was 78% and was not different from that of the general population. There were no systemic progressions, but 17% of patients (n=72) had localized progression.

Localized AL is associated with a relatively distinct pattern of organ involvement. The initial laboratory evaluation to exclude systemic disease could be limited to serum and urine immunofixation in most patients. Recurrence after first-line therapy is common, but long-term outcomes are excellent.