Light Chain Deposition Disease - presenting with Cystic Pulmonary Disorder as primary manifestation - A case report

Light Chain Deposition Disease (LCDD) is a rare disease characterized by deposition of abnormal, non-amyloid, monoclonal light chains in tissues, potentially leading to organ dysfunction or failure. In most cases, LCDD occurs secondary to lymphoproliferative conditions, such as underlying B-cell disease. LCDD mainly affects the kidneys, liver and heart. Pulmonary LCDD (pLCDD) is less common, usually asymptomatic and acknowledged post-mortem. Furthermore, pLCDD exists in three forms i.e. an airway dominant, a nodular and a cystic form, which can all arise from a dominant B-cell clone restricted to the lung without multisystemic involvement. Herein we present a young man with isolated pLCDD manifested by cystic pulmonary involvement. Surgical lung wedge resection provided histological diagnostic confirmation showing extracellular deposits, which were negative by Congo red staining but positive for κ-light chain by immunohistochemistry and mass spectrometry. There was no sign of underlying hematological disease.