Light Chain Amyloidosis: A Case Presentation and Review

Abstract

In 1977, an asymptomatic 68-year-old woman underwent biopsy of a supraclavicular node that had been detected at the time she presented for breast biopsy. While the breast biopsy was benign, pathology from the lymph node revealed amyloid. For unclear reasons, no further evaluation or treatment was undertaken then. Two years later, a paratracheal node was noted during screening chest x-ray. Biopsy again showed amyloid. At that time, the patient's spleen and liver were enlarged. Howell-Jolly bodies were identified on peripheral blood smear, suggesting hyposplenism. This was confirmed by a radionuclide liver-spleen scan, which showed decreased splenic uptake (1). Initial 24-hour urine specimen collected 5.1 g of protein, 64.4% of which was albumin by urine protein electrophoresis (Figure ​(Figure11). Despite significant albuminuria, her serum albumin was 3.9 g/dL. Quantitative immunoglobulins were depressed, with IgG of 385 mg/dL, IgA of 72 mg/dL, and IgM of 140 mg/dL. While serum immunofixation electrophoresis (IFE) was negative for monoclonal light chain (“Bence Jones”) protein, urine IFE did detect a monoclonal lambda protein (Figure ​(Figure22). Skeletal x-rays showed no lytic lesions. Bone marrow aspirate (Figure ​(Figure33) and biopsy revealed plasmacytosis of 10% to 15% and light chain amyloid, with a kappa:lambda ratio of 1:50. Subsequent renal biopsy also showed lambda light chain amyloid. Figure 1 Urine protein electrophoresis of our patient, showing heavy albuminuria but no clear-cut monoclonal protein. Anode is on the right. Urine concentrated 50x. Figure 2 Urine immunofixation electrophoresis from our patient. The dense, broad anodal band against anti–whole human serum (AWHS) in the upper left column indicates albumin. Antisera to kappa and lambda light chains showed a homogeneous band against the ... Figure 3 Bone marrow aspirate of our patient. Congo red staining revealed amorphous eosinophilic material lying free in the marrow space. These areas displayed apple-green birefringence under polarized light, confirming amyloid. After initiation of low-dose prednisone and colchicine, the patient's hepatomegaly, functional hyposplenism, albuminuria, and Bence Jones proteinuria resolved. She was maintained on this therapy for more than a decade. Despite eventual discontinuation of these medications, she remained in clinical complete remission through her last follow-up, 21 years after presentation. She died the following year of an unknown cause.