[Secondary infection of traumatic pulmonary cyst misdiagnosed as cholesterol encapsulated pleural effusion: a rare case and review of literature].

Pulmonary cyst is a relatively common benign lesion. It is easy to be misdiagnosed when the cyst complicated with infection. This paper reported a case of a giant traumatic pulmonary cyst (diameter 10 cm) combined with chronic infection. Firstly, the patient was diagnosed as cholesterol pleurisy after undergoing thoracoscopic biopsy. With repeated pleural effusion, the patient was scheduled for right anterolateral thoracotomy, which showed a thin-walled cyst (10 cm in diameter) attached to parietal and diaphragm, with the stem of cavity originated from the right lower lobe after the cyst cavity was dissociated. Pathological examination revealed that it was apseudocyst, which could be diagnosed as traumatic pulmonary cyst combined with chronic infection according to history of trauma. After undergoing right lower lobectomy and stripping of fiberboard, the prognosis was good. Traumatic pulmonary cyst, which was discovered interval 10 years after chest trauma, was rare. Traumatic pulmonary cyst combined with cholesterol cystic fluid was very rare. Huge pulmonary cyst complicated with infection was easily misdiagnosed as loculated pleural effusion. Therefore, to be correct diagnosis and treatment, clinician must carefully ask medical history. In addition, early image examination should be considered in those patients with chest trauma whether there are clinical symptoms or not.