Objective  To investigate the clinical characteristics and computed tomography (CT) features of cystic lung cancer to improve the diagnostic accuracy of such lesions.

  Methods  The CT features of 55 patients enrolled in The Fourth Hospital of Hebei Medical University from September 2016 to March 2019 with surgically and pathologically confirmed cystic lung were retrospectively analyzed. The clinical characteristics (including age, sex, symptoms, smoking history, emphysema, and location), CT features (including classification, cystic morphology, septation, lobulation, spiculation, pleural retraction sign, cyst wall thickness, nodules on the wall, and extracystic features), and pathological types were summarized.

  Results  Among the 55 patients, 19 were females and 36 were males; the average age was (60.6±8.2) years. Thirty-one patients had clinical symptoms of cough, expectoration, chest pain, and fever. Twenty-eight patients had a smoking history. Nine patients had combined pulmonary emphysema. Forty-three lesions were located in the peripheral lung. According to the classification proposed by Mascalchi, 12 patients had typeⅠ lesions, 5 had type Ⅱ, 20 had typeⅢ, 18 had type Ⅳ, and 43 had irregularshaped lesions. Septation was found in 29 patients, lobulation in 21, spiculation in 11, and pleural retraction sign in 14. Twenty-eight patients had cystic spaces associated with ground-glass opacities and 27 patients had lesions with a solid density. Among the 55 patients, 51 had adenocarcinomas (including invasive and microinvasive adenocarcinomas), 3 had adenosquamous carcinomas, and 1 had squamous cell carcinoma.

  Conclusions  The CT features of cystic lung cancer are characteristic and accompanied by common signs of peripheral lung cancer. Diagnostic accuracy can be improved by combining the CT features of cystic spaces and the surrounding changes.