Immunoglobulin light chain amyloidosis is diagnosed late in patients with preexisting plasma cell dyscrasias.

AL amyloidosis (AL) is rare and frequently remains undiagnosed until organ function is compromised, even among patients with known pre-existing untreated plasma cell dyscrasias (PCD). We identified 168 patients with AL amyloidosis who had a prior untreated PCD. The earliest symptom or sign (s/s) was defined as the first symptom reported by the patient that could be attributed to organ dysfunction caused by AL. The interval from the time of development of s/s to the establishment of diagnosis of AL (Interval-SA) was calculated. PCD diagnosis preceded recorded onset of s/s in 75% (114/152) of patients, with a median interval-SA for this group of 10 months. PCD was diagnosed after s/s in 25% (38/152) of patients, with a median interval-SA of 20 months. Overall survival (OS) from diagnosis of AL was not different between the two groups. AL amyloidosis patients with an identified pre-existing PCD had less advanced cardiac disease at AL diagnosis when compared to a control group of AL patients without pre-identified PCD. Long-term OS was not significantly superior among patients with a pre-identified PCD. In patients with "asymptomatic" PCD, symptoms and signs of AL amyloidosis should be solicited, since timely diagnosis is important in AL amyloidosis.