Cardiomyopathy Without Amyloid Deposit in Systemic Light Chain Deposition Disease

A 47-year-old woman with persistent congestive heart failure symptoms diagnosed 3 months earlier at another hospital. Her laboratory tests indicated an increased NT-proBNP level of 5,729 pg/mL. Her echocardiography showed left ventricular hypertrophy with a wall thickness and mass index of 13.7 mm and 100 g/m², respectively, and diastolic dysfunction (Figure 1A and B). The electrocardiogram displayed low voltage with Q waves in V1–V2 (Figure 1C). The free light chain (FLC) analysis indicated significantly increased serum FLC-Lambda levels (638.87 mg/L) and an abnormal κ/λ ratio of 0.01. We conducted endomyocardial biopsy, revealing interstitial fibrosis without amyloid deposition (Figure 1D-F). Bone marrow examination confirmed 13% plasma cell proliferation, diagnosing light chain deposition disease (LCDD). Renal tissue examination revealed FLC-λ deposition. After a 3-month bortezomib, lenalidomide, and dexamethasone regimen, FLC-κ levels decreased to 9.85 mg/L, but cardiac functions worsened.

Figure 1. Images and histological analyses in a case with cardiac light chain deposition disease. (A) Transthoracic echocardiographic image showing left ventricular wall thickness with disproportionate interventricular septal enlargement, resulting in a ‘speckled’ appearance and small pericardial effusion (parasternal long-axis view). (B) Regional longitudinal strain, assessed by 2-dimensional speckle-tracking echocardiography. The reduction in global longitudinal strain is particularly observed in the basal and mid-ventricular segments, manifesting as an ‘apical sparing’ pattern. The mean global longitudinal strain was −8.5%. (C) Electrocardiogram; The electrocardiogram of the patient reveals characteristic findings, including low voltage in the limb leads (QRS amplitude <5 mm in leads II, III, aVR, aVF) and a pseudo-infarct pattern (pathologic Q waves in V1, V2, V3, accompanied by the loss of R wave progression). (D, G) Histological analyses of endomyocardial biopsy specimens. (D) Trichrome staining: The blue areas signify significant interstitial fibrosis, original magnification ×100. (E) Congo red staining; The Congo red stain did not show extracellular deposition of amyloid fibrils in the myocardial interstitium, original magnification ×100. (F) Immunofluorescence using anti-κ light chain antibody; the myocardial interstitium shows a negative reaction, original magnification ×100. (G) Immunofluorescence using anti-λ light chain antibody; The immunostaining with anti-λ light chain antibodies reveals intense positivity in the myocardial interstitium, original magnification ×100.

aVR = augmented vector right; aVF = augmented vector foot.

LCDD is a rare and severe immunologic disorder caused by the excessive accumulation of abnormal light chain proteins from specific plasma cells, leading to deposition and organ damage across multiple systems. Unlike cardiac amyloidosis, where amyloid proteins accumulate in beta-sheet formations within cardiac tissues, LCDD involves non-amyloidogenic FLC aggregates, triggering unclear damage mechanisms and potential inflammatory and fibrotic reactions.¹⁾,²⁾

There is currently no agreed-upon treatment protocol for cardiac LCDD. Some cases suggest potential reversibility with plasma cell dyscrasia chemotherapy, while others result in fatal cardiac failure despite conservative treatment.³⁾,⁴⁾ The prognosis of LCDD varies, with around 32% of patients showing cardiac involvement and a poor prognosis.⁵⁾ This is the first reported case of LCDD with cardiac and renal involvement in Korea.

This study protocol was reviewed and approved by the Institutional Review Board (IRB) of the School of Medicine, Kyungpook National University (IRB No. 2024-01-003), Daegu, Korea.