Foregut cysts.

Foregut cysts frequently cause symptoms in the first three decades of life. The symptoms consist of dyspnea, wheezing, cough and sputum, dysphagia, stridor, and those associated with right heart strain. Symptoms and the radiological appearance of the uncomplicated cyst mimic mediastinal tumour and mediastinal obstruction. The symptoms and radiological appearance of the ruptured infected cyst simulate those of lung abscess, diaphragmatic hernia, ruptured hydatid cyst, cavitated peripheral carcinoma and pulmonary tuberculosis. In this series the differentiation from other cysts was made thus: with intralobar sequestration, a systemic arterial blood supply was demonstrated; with hydatid cyst, there was a positive intradermal skin test and (radiologically) following rupture, the appearance of a pericystic pneumatocele followed by the water-lily sign was diagnostic; with emphysematous cysts, the signs of associated bronchitis were present; in the presence of pseudocysts, there was a previous history of lung abscess, staphylococcal infection or tuberculosis. Cysts should be removed when first diagnosed.