Light chains, heavy consequences: a pulmonary tale

SESSION TITLE: Systemic Diseases: Consequent or Subsequent Lung Involvement SESSION TYPE: Case Reports PRESENTED ON: 10/11/2023 10:30 am - 11:30 am INTRODUCTION: Light chain deposition disease (LCDD), a rare and devastating disease, can lead to both pulmonary cystic changes and cardiomyopathy. This condition is characterized by the deposition of monoclonal light chain proteins in tissues, typically the kidney and liver, resulting in abnormal organ function and structural changes. In this case report, we present an atypical presentation of LCDD causing both restrictive cardiomyopathy and pulmonary cystic disease. CASE PRESENTATION: A 49-year-old male was admitted for two months of progressive dyspnea, cough, and palpitations. On arrival, he was hypertensive and tachycardic. Physical examination was remarkable for bilateral crackles and lower extremity edema. Initial laboratory investigation revealed mild normocytic anemia, normal renal and liver panel, brain naturetic peptide of 767 pg/mL, and urinalysis with proteinuria and hematuria. Chest X-ray (Figure 1) revealed bilateral lung reticular opacities, most prominent at the bases. Chest Computed Tomography (Figure 2) revealed bilateral diffuse cystic changes, bilateral pleural effusions, and a 1-cm pulmonary nodule. Transthoracic echocardiogram demonstrated mild concentric left ventricular hypertrophy, severely depressed left ventricular systolic function, global hypokinesis, and left ventricular diastolic dysfunction. Left heart catheterization revealed non-obstructive disease. Further studies included negative SS-A/SS-B and ANA antibodies, elevated 24hr urine protein of 1,300mg/24 hours, lambda quantitative free light chain elevation of 629.53mg/L, and Kappa/Lambda free chain ratio reduced at 0.02. SPEP demonstrated a possible monoclonal spike in the gamma region which was subsequently characterized by immunofixation electrophoresis as IgD lambda monoclonal gammopathy with free lambda light chain disease. Ultimately, bone marrow biopsy of the left iliac crest was obtained and confirmed diagnosis of LCDD. Although the lungs were not biopsied, the patient was presumed to have pulmonary cystic lesions related to LCDD and has started treatment with daratumumab, bortezomib, and dexamethasone. He has symptomatically improved and is pending repeat imaging. DISCUSSION: LCDD is difficult to diagnose and treat because it is not commonly encountered in clinical practice. Pulmonary manifestations occur when light chain proteins cause alveolar destruction and cystic lung disease. The extent of pulmonary involvement determines clinical presentation, which can include dyspnea, chest pain, hemoptysis, and/or asymptomatic imaging abnormalities. Pulmonary cystic changes are a common feature of LCDD, with cystic lesions containing vessels that may lead to hemoptysis. Diagnosis of LCDD requires tissue biopsy and is often associated with multiple myeloma. Treatment involves removal of the light chains, which is similar to multiple myeloma management, although no specific therapy exists for PLCDD. Prognosis varies on severity and amount of organ involvement but median survival is between 5-14 years after diagnosis. Lung transplant may be considered if disease progression continues despite treatment, but its efficacy remains uncertain. CONCLUSIONS: Given its unique presentation, pulmonary LCDD requires a high degree of suspicion to avoid misdiagnosis and should be considered in the differential diagnosis for cystic lung disease. The diagnosis and treatment of this condition requires a collaborative and multidisciplinary approach to target the affected organs. REFERENCE #1: Wei P, Tao R, Liu Y, Xie H, Jiang S, Yu D, Lu H, Cao W. Pulmonary light chain deposition disease: a case series and literature review. Ann Transl Med. 2020 May;8(9):588. doi: 10.21037/atm-20-2708. REFERENCE #2: Bhargava P, Rushin JM, Rusnock EJ, Hefter LG, Franks TJ, Sabnis SG, Travis WD. Pulmonary light chain deposition disease: report of five cases and review of the literature. Am J Surg Pathol. 2007 Feb;31(2):267-76. doi: 10.1097/01. REFERENCE #3: Pozzi C, Fogazzi GB, Banfi G, et al. Renal disease and patient survival in light chain deposition disease. Clin Nephrol 1995;43:281-7. DISCLOSURES: No relevant relationships by Fernando Hernandez No relevant relationships by Lara Jones No relevant relationships by Jay Peters No relevant relationships by Nicholas Schlund