Etiological Distribution And Differential Diagnosis Of Diffuse Pulmonary Cystic Lesions

Part 1 The etiology distribution and differential diagnosis of the diffuse cystic lung diseasesBackground:The diffuse cystic lung diseases (DCLD) are characterized by the presence of multiple thin-walled air filled spaces within the pulmonary parenchyma. Increasing number of diseases have been associated with this presence and the differential diagnosis is broad.Objective:We aim to explore proportion of the diseases with the presence of DCLD based on the data collected in our center, In the meantime, to describe the clinical features and differential diagnostic points. We will summary the stepwise diagnosis approach in the end.Methods:Clinical data of patients admitted in Pecking Union Hospital lymphangioleiomyomatosis outpatient department were gathered. Patients whose pulmonary CT present as the multiple cysts were enrolled. A retrospective study was executed to make diagnosis based on the criteria and describe the demographic, clinical, laboratory, pathological, radiological features of different causes of DCLD. We summary the proportion of different causes, the differential diagnostic points and the stepwise diagnosis approach.Results:398 patients whose CT present as DCLD were enrolled.287 patitents were diagnosed with lymphangioleiomyomatosis. The other 111 patients were diagnosed with Sjogren’s syndrome(17), Birt-Hogg-Dube syndrome(16), pulmonary Langerhans cell histiocytosis(7), pulmonary malignant lesions(6), bronchial dilatation(5), pulmonary fibrosis(2), marfan syndrome(1), amyloidosis(1), congenital cystic adenomatoid malformation of the lung(1), microscopic polyangiitis(1), and parts of the patients had not been diagnosed(54). Two of the seventeen patients diagnosed with Sjogren’s syndrome were diagnosed with light chain deposition disease. The demographic, clinical, laboratory, pathological, radiological features and the differential diagnostic points were described. The stepwise diagnosis approach was proposed.Conclusion:Patients in the Pecking Union Hospital lymphangioleiomyomatosis outpatient department were mainly diagnosed with lymphangioleiomyomatosis. The other main causes were Sjogren’s syndrome, Birt-Hogg-Dube syndrome, pulmonary Langerhans cell histiocytosis and pulmonary malignant lesions. Parts of the DCLD can’t be diagnosed accuratly. Patients present as DCLD can be distinguished by the demographic, clinical, laboratory, pathological, radiological features.Part 2 The diagnostic value of transbronchial biopsy in lymphangioleiomyomatosisBackground:Transbronchial lung biopsy (TBLB) in diagnosis of LAM is not universally accepted although TBLB is commonly performed in diffuse lung diseases. We aim to examine the diagnostic value and safety of TBLB in LAM patients based on the data collected in our center.Method:Medical records of 404 LAM or patients with diffuse cystic lung diseases were examined and some of them were interviewed via telephone, online survey and mail. All available pathology slides were reviewed by an experienced LAM pathologist (H. Liu).Results:The pathology results of 47 patients were available. In general, the positive rate of TBLB for diagnosis of LAM was 42.6%. The positive rate of the patients who took TBLB in Pecking Union Medical College Hospital and in other hospitals were 63.2% and 28.6%, respectively. (p<0.05). Three biopsies/specimen were generally required for a patient. The rate of pneumothorax was 10%. No severe hemoptysis was reported.Conclusion:TBLB could be applied safely for LAM patients in experienced diffuse lung disease centers. The positive rate could be up to 63.2%.