Bronchogenic cysts

Case report,Pi Fengling 2015-08-13,Male,48yHistory:Breathlessness, not associated with cough or expectoration. No hemoptysis.,Bronchogenic cysts,01,Epidemiology,02,Clinical presentation,04,Radiographic features,06,Differential diagnosis,Contents,03,Pathology and Distribution,05,Treatment and prognosis,Introduction,Bronchogenic cysts form as a result of abnormal budding of the bronchial tree during embryogenesis (between 4th-6th weeks)( type of bronchopulmonary foregut malformation). It is also considered the commonest of foregut duplication cysts.,Epidemiology,Bronchogenic cysts are rare congenital lesions accounting for only 5-10% of paediatric mediastinal masses . The incidence of mediastinal cysts is equal between the sexes whereas intrapulmonary cysts are reported to have a male predilection .,Clinical presentation,In many instances, bronchogenic cysts are asymptomatic and are found incidentally when the chest is imaged. When large, mass effect may result in bronchial obstruction leading to air trapping and respiratory distress. An alternative presentation may occur when the cyst becomes infected.,Pathology,Bronchogenic cysts are lined by secretory respiratory epithelium (cuboid or columnar ciliated epithelium纤毛柱状上皮) . The wall is made up of tissues similar to that of the normal bronchial tree, including cartilage, elastic tissues, mucous glands and smooth muscle . They contain fluid (water), variable amounts of proteinaceous material, blood products, and calcium oxalate . They are rarely multiple.,Microscopic view of bronchogenic cyst. (A) The mass contained smooth muscle cells (white arrow) and squamous epithelial cells (black arrow). (B) The lesion was lined by pseudostratified ciliated columnar epithelium (white arrow) and the parenchymal portion contained mature hyaline cartilage (black arrow). HE, 100.,* usually does not communicate with the tracheo-bronchial tree* subcarinal, right paratracheal and hilar locations most common,* typically perihilar* predilection for lower lobes,* extending across the diaphragm and appearing dumb-bell shaped,Distribution comments,mediastinal,other,intrapulmonary,Radiographic features,Although bronchogenic cysts are usually fluid filled, occasionally a communication may develop following infection, resulting in an air-filled cystic structure +/- an air-fluid level.,Plain film,The cysts usually appear as soft-tissue density rounded structures, sometimes with compression of surrounding structures.Occasionally such compression can lead to air-trapping and a hyperlucent hemithorax . As the cysts may contain calcium oxalate, dependent layering of calcific density material (milk of calcium) may on occasion be seen.,CT,Typically appear as well circumscribed spherical or ovoid masses of variable attenuation. Variable fluid composition explains the different CT attenuations observed.Approximately 50% are fluid density (0-20 HU), however a significant proportion are of soft tissue density (30 HU) or even hyperdense to surrounding mediastinal soft tissues . CT is better able to detect calcium oxalate (milk of calcium) layering dependently.Usually no solid contrast enhancement.,MR,T1 WI variable signal intensity, from low (similar to fluid) to high (due to protein content)fluid fluid level has also been reported, attributed to layering of variable fluid content .T2 WIusually high signal intensity due to fluid contents,Treatment and prognosis,The choice of treatment is somewhat controversial. Some authors advocate surgical excision of all cysts given their tendency to become infected or rarely, to undergo malignant transformation . Increasingly, these lesions are treated with transbronchial or percutaneous aspiration under CT guidance to both confirm the diagnosis and to treat them. Small lesions can be followed, however they do have a tendency to increase in size over time, sometimes rapidly .,Differential diagnosis,congenital cysts and malformationspericardial cystcystic hygroma and lymphangiomaschwannoma anterior or lateral meningocele(脑脊膜膨出)oesophageal duplication cystthyroid colloid cystthymic （胸腺）cyst,intrathoracic pancreatic pseudocyst for retroperitoneal bronchogenic cysts or for pancreatic pseudocysts that extend intrathoracically through the aortic hiatus or oesophageal hiatus,abscess(es)enlarged lymph nodes (especially if centrally necrotic）focal haematoma: different clinical contextbronchiectasia,If complicated, e.g. with infection or haemorrhage, also consider,pulmonary massescongenital pulmonary airway malformation (CPAM)pulmonary sequestrationmetastaseslung cancer,Thank you ！,pericardial cyst,Pericardial cyst,preferentially found in the right anterior cardiophrenic angle（ the commonest location）, but can be found almost anywhere adjacent to the heart.,Cystic hygroma,Cystic hygroma,usually occur in the fetal/infantile and paediatric populations with most lesions presenting by the age of two.can present with pain, dyspnoea, infection, haemorrhage or respiratory compromise. occur most commonly in the neck, which is then also termed nuchal cystic hygroma (occurs in 80% of cases) and axilla, with only 10% of cases extending to the mediastinum and only 1% confined to the chest .,schwannoma,schwannoma,spinal nerve rootsintercostal nerves: intercostal nerve schwannomaposterior mediastinumcystic and fatty degeneration are common .haemorrhage occurs in 5% of cases calcification is rareperipheral arachnoid cysts may be associatedperitumoural oedema may be seen,anterior or lateral meningocele,It results from hernia