[An unusual cause of cystic lung disease: light chain deposition disease]. / Une cause rare de maladie kystique pulmonaire: maladie à dépôts de chaînes légères d'immunoglobuline.

INTRODUCTION: Light chain deposition disease is a rare clinical entity characterized by deposition of monoclonal immunoglobulin light chains in organs. The kidneys are almost always affected, while the lung manifestations that have been reported, including nodular or diffuse disease, especially cystic lesions, are unusual. CASE REPORT: We report the case of a 60-year-old man with a diffuse infiltrative lung disease characterized by numerous apical cysts. The diagnosis of light chain deposition cystic lung disease was obtained by surgical lung biopsy. Light chain deposits in the salivary glands were the only extrapulmonary manifestation. Despite 12 chemotherapy cycles, the patient's lung function and radiological appearances worsened. CONCLUSION: This is the fourth case describing a cystic lung disease due to light chain deposition in the literature. It highlights the need for comprehensive investigations so as not to miss this rare cause of cystic lung disease, which appears to be related to a primary pulmonary lymphoproliferative disorder. The only treatment that appears to be effective is lung transplantation.

[Pulmonary sarcoidosis developing during treatment with etanercept]. / Sarcoïdose pulmonaire apparue sous étanercept.

INTRODUCTION: TNF blockers are widely used to treat inflammatory rheumatic diseases and also in the treatment of extrapulmonary sarcoidosis. TNFα plays a major role in the development and persistence of sarcoid granulomata. However, recent studies have reported the involvement of anti-TNF therapies in the development of granulomatosis associated with the clinical and radiological features of sarcoidosis. CASE REPORT: A 54-years-old man with ankylosing spondylitis was treated with etanercept for two years. He was admitted with symptoms of bronchitis associated with radiological evidence of bilateral pulmonary nodules and a right upper lobe infiltrate. Anti-TNF therapy was stopped even though the patient had received 3 months of prophylactic treatment with rifampicin and isoniazid before starting etanercept. Bronchoalveolar lavage excluded infection, particularly tuberculosis. The chest CT-scan showed bilateral pulmonary nodules with peribronchovascular micronodules and enlarged mediastinal lymph nodes. Surgical lung biopsy was performed and revealed non-caseating granulomata. All the data were consistent with a diagnosis of pulmonary sarcoidosis. The patient remained symptomatic despite discontinuation of etanercept for ten months. Corticosteroids were then introduced, leading to a clinical, functional and radiological improvement. CONCLUSION: This case report underlines the importance of studying the pulmonary complications of TNF blockers. The first priority is to exclude tuberculosis but a diagnosis of sarcoid-like granulomatosis has to be considered. Twenty-three cases have been described in the literature to date.