Cardiac light-chain deposition disease and hints at diagnosing: a case report

Abstract

Background: Light-chain deposition disease (LCDD) is a systemic disorder characterized by non-amyloidotic light-chain deposition in various organs with Bence-Jones type monoclonal gammopathy. Although known as monoclonal gammopathy of renal significance, it may involve interstitial tissue of various organs, and in rare cases, proceeds to organ failure. We present a case of cardiac LCDD in a patient initially suspected of dialysis-associated cardiomyopathy.

Case summary: A 65-year-old man with end-stage renal disease requiring haemodialysis presented with fatigue, anorexia, and shortness of breath. He had a history of recurrent congestive heart failure and Bence-Jones type monoclonal gammopathy. A cardiac biopsy performed for suspected light-chain cardiac amyloidosis was negative for diagnostic Congo-red stain, however, paraffin immunofluorescence examination for light-chain suggested diagnosis of cardiac LCDD.

Discussion: Cardiac LCDD may go undetected leading to heart failure due to lack of clinical awareness and insufficient pathological investigation. In heart failure cases with Bence-Jones type monoclonal gammopathy, clinicians should consider not only amyloidosis but also interstitial light-chain deposition. In addition, in patients with chronic kidney disease of unknown cause, investigation is recommended to rule out cardiac light-chain deposition disease concomitant with renal LCDD. Although LCDD is relatively rare it occasionally affects multiple organs; therefore, it would be better to describe it as a monoclonal gammopathy of clinical significance rather than one of renal significance.

Keywords: Cardiac light-chain deposition disease; Cardiac magnetic resonance T1 mapping; Case report; Monoclonal gammopathy of clinical significance; Paraffin-immunofluorescence.

Figure 1

Cardiac magnetic resonance four-chamber view showing diffuse mild thickness of the left ventricular wall (A). Native T1 mapping showed significantly prolonged native T1 time comparable with cardiac amyloidosis. The control T1 value in our hospital is 1245.3 ± 37.5 ms (B).

Figure 2

Cardiac biopsy histopathology. Immunofluorescence for kappa light-chain on formalin-fixed paraffin-embedded section showed positive staining around each myocardium (A, arrow) in contrast to lambda light chain (B). Electron microscopy revealed powdery deposition in the perimyocardium and interstitial areas (C, arrowhead) indicating kappa light-chain deposition.

Figure 3

Clinical course. Levels of both serum-free light chain-κ and plasma brain natriuretic peptides dramatically decreased after starting daratumumab, lenalidomide, and dexamethasone. *Daratumumab, lenalidomide, and dexamethasone regimen: lenalidomide 5 mg/day (21days); daratumumab and dexamethasone 1800 and 20 mg/week, respectively delivered on Days 1, 8, 15, and 22 of treatment.

Figure 4

Amino acid sequence of the pathogenetic clone. Comparison of amino acid sequences among germline, benign Bence-Jones protein (LEN) and the present case (KNZ4-1). LEN had one mutation in contrast to KNZ4-1, which had five including four hydrophobic residues. In addition, KNZ4-1 had one additional glycosylation with mutation of 31st amino acid (N > T). *LEN is a known benign Bence-Jones protein.