CT Findings Of Diffuse Cystic In Lungs

BackgroundThere are many kinds of diseases with diffuse cysts in lung,which can be caused by different causes.Therefore,the diagnosis and differential diagnosis are complicated.CT is usually the most important and best method for evaluating pulmonary diffuse cystic diseases.At present,there are few literatures about CT manifestations of diffuse cystic changes in the lung,because a variety of cystic lesions are rare diseases,especially for three rare diseases: pulmonary lymphangioleiomyomatosis(PLAM),pulmonary Langerhans cell histiocytosis(PLCH)and lymphocytic interstitial pneumonia(LIP).Purpose The analysis of CT features of pulmonary diffuse cystic diseases is helpful to summarize and compare the characteristics of three relatively common diseases(PLAM,PLCH and LIP),narrow the scope of diagnosis and differential diagnosis of these diseases and avoid diagnosis by biopsy as far as possible.Materials and methods Cases of pulmonary lymphangioleiomyomatosis(PLAM),pulmonary Langerhans cell histiocytosis(PLCH)and lymphocytic interstitial pneumonia(LIP)confirmed by pathology in the first affiliated Hospital of Guangzhou Medical University from January 2010 to October 2019 were collected,including 77 cases of PLAM,21 cases of PLCH and 5 cases of LIP.The clinical data and CT signs of the three were analyzed and compared.Statistical methods: Comparison of measurement data,using ANOVA and LSD;Chi-square test is used to compare the three groups of counting data;Binary Logistic regression analysis was used to analyze the correlation between the extrapulmonary manifestations of PLAM and the occurrence of small pulmonary nodules.Result The average age of 77 patients with PLAM was 38.0 ±9.9 years,which were all female,including 45 cases of simple lung tissue involvement and 32 cases of extrapulmonary organ lesions(including 9 cases of TSC-LAM and 23 cases of non-TSC-LAM).2 patients had a history of smoking.The main clinical manifestations were shortness of breath(48 cases),chest pain(10 cases),dyspnea(7cases),cough and sputum(24 cases),chest tightness(14 cases)and hemoptysis(3cases).There were only diffuse cystic changes in X cases and diffuse cystic changes with small nodules in 12 cases,in which the average diameter of the largest cystic cavity was 19.1±1.9mm,,the thickness of the thickest cyst wall was 1.6±0.1mm.Most of the cysts were mainly distributed in the two upper lung fields in 7 cases,randomly distributed in 70 cases,round and quasi-round in 74 cases,irregular in 3cases,blurred boundary of the cyst wall in 14 cases,and no septum was found in 77 cases.The intermural vessels were partially compressed in 6 cases,bronchovascular bundle thickened in 2 cases,interlobular septal thickening in 4 cases,blurring and exudation in 42 cases.Pneumothorax occurred in 25 cases,pleural effusion in 21 cases,chylothorax in 1 case and pericardial effusion in 3 cases.Abdominal CT showed renal angiomyolipoma in 23 cases,including 2 cases of renal angiomyolipoma after resection,8 cases of hepatic angiomyolipoma,1 case of spleen.There were 12 cases of abdominal lymph node enlargement or retroperitoneal lymphangioma.There were 9 cases with tuberous sclerosis and 1 case with bone involvement.The average age of 21 patients with PLCH was 28.9 ±14.1 years old,including 18 males and 3 females,and 17 patients had a history of smoking.The main clinical manifestations were shortness of breath(11 cases),chest pain(2 cases),cough and sputum(15 cases),dyspnea(1 case),chest tightness(3 cases)and hemoptysis(1case).There were only diffuse cystic changes in 4 cases and diffuse cystic changes with small nodules in 17 cases,in which the average diameter of the largest cyst was25.4±4.2mm,,the thickness of the thickest cyst wall was 2.7mm ±0.3mm.The cysts were mainly distributed in the two upper lung fields in 8 cases,the bilateral costal diaphragmatic angle was not involved in 6 cases,and randomly distributed in 7 cases.The cysts were round or quasi-round in 5 cases,irregular in 4 cases and partial cystic fusion in 12 cases.The wall of the cyst was blurred in 19 cases and the septum was seen in 15 cases.Partial compression of blood vessels between the cyst wall was found in 1 case,bronchovascular bundle thickening in 11 cases,interlobular septal thickening in 12 cases,blurring and exudation in 18 cases.Pneumothorax occurred in 4 cases,pleural effusion occurred in 4 cases,mediastinal lymph node enlargement and pericardial effusion were not found in 4 cases.The average age of 5 cases of LIP was 39.6±13.5 years old,which were all female.The main clinical manifestations were cough and sputum(4 cases),shortness of breath(1 case)and chest tightness(1 case).There were only multiple cystic changes in both lungs in 4 cases and multiple cystic shadow with small nodules in 1 case,in which the average maximum diameter,thickest wall thickness were 8.1mm±2.2mm,2.2mm±0.4mm.respectively.The cysts of 3 patients were randomly distributed,2patients were distributedalong the subpleural、bronchial vascular bundle.The cysts of5 patients were round or quasi-round.The boundary of the cyst wall was blurred and intracapsular septum could be seen in 5 cases.Bronchovascular bundle thickening was found in 3 cases and interlobular septal thickening and blurring and exudation were found in 5 cases.2 cases were complicated with pleural effusion and 1 case with mediastinal lymph node enlargement.No pneumothorax and pericardial effusion were found.Through statistical analysis,the following results were obtained:1.There were significant differences in age,sex and smoking history between PLAM and PLCH.There were significant differences between PLCH and LIP in sex and smoking history.There was no significant difference in age of onset,and there was no significant difference between PLAM and LIP in these three aspects.2.There was no significant difference in the incidence of clinical symptoms such as shortness of breath,chest pain,dyspnea,cough,sputum,chest tightness and hemoptysis among PLAM,PLCH and LIP groups.3.There were significant differences in the thickest cyst wall thickness and thinnest cyst wall thickness between PLAM and PLCH,but there was no significant difference between PLAM and LIP and between PLCH and LIP.There was significant difference between PLAM and LIP and between PLCH and LIP in the maximum diameter of the cyst,on the contrary,there was no significant difference between PLAM and PLCH.There was no significant difference in the minimum cyst diameter among the three groups.4.There were significant differences in the distribution,shape,boundary,intracapsular septum,pericystic nodule,interlobular septal thickening,bronchovascular bundle thickening,blurring and exudation between PLAM and PLCH.5.There were significant differences in the boundary of cysts,thickening of bronchovascular bundle and thickening of interlobular septum between PLAM and LIP,but there was no significant difference in the distribution,shape,intracapsular septum,surrounding nodules,blurring and exudation of other cysts.6.There was significant difference between PLCH and LIP in the boundary and septum of the cysts,but there was no significant difference in the distribution and shape of the cysts,nodules around the cysts,thickening of interlobular septum,thickening and blurring of bronchovascular bundles,exudation and so on.7.There was no significant difference among the three groups in the shape of blood vessels between the cyst wall,pneumothorax,pleural effusion,pericardial effusion and mediastinal lymph node enlargement.8.There Was significant difference in the incidence of abdominal lymphadenopathy/retroperitoneal lymphangioma between PLAM patients with pulmonary nodules and patients without nodules,but there was no significant difference in the incidence of other extrapulmonary organs(kidney,liver,spleen,brain).Conclusion:1.The main differential points of PLAM and PLCH were age,sex,smoking history,thickest cyst wall thickness,thinnest cyst wall thickness,cyst cavity distribution,shape,boundary,intracapsular septum,pericystic nodules,interstitial thickening,bronchovascular bundle thickening,blurring and exudation shadow.2.The main differential points of PLAM and LIP are as follows: the maximum diameter of the cyst,the boundary of the cyst,the thickening of bronchovascular bundle and the thickening of stroma.3.The main differential points of PLCH and LIP were sex,smoking history,maximum diameter of cyst,boundary of cyst and intracavitary septum.4.In PLAM,patients with abdominal lymph node enlargement/retroperitoneal lymphangioma were more likely to have nodular shadow in the lung than those without abdominal lymph node enlargement/retroperitoneal lymphangioma.