Abstract: Objective To analyze the imaging and clinicopathological features of cystic lung cancer with signet ring syndrome. Methods The CT features and clinical and pathological data of 23 patients with cystic lung cancer diagnosed by chest CT and surgery in our hospital from January 2016 to December 2019 were analyzed retrospectively. They were divided into signet ring sign type cystic lung cancer group and other types of cystic lung cancer group according to whether they had signet ring sign or not. Results There were 9 patients with signet ring type cystic lung cancer and 14 patients with other types of cystic lung cancer. In terms of imaging，the lesions were peripheral type. The proportion of ground glass composition and intracapsular septum on CT of signet ring type cystic lung cancer was less than that of other types. There was no significant difference in marginal morphology and adjacent structures between the two types. The pathology was adenocarcinoma，among which papillary adenocarcinoma and acinar adenocarcinoma were the most common in signet ring type cystic lung cancer，while adherent growth was the main type in other types of cystic lung cancer（P < 0.05）. All patients had no lymph node metastasis. however， the proportion of intravascular tumor thrombus in signet ring type cystic lung cancer was significantly higher than that in other types（P < 0.05）. There was no significant difference in gene mutation between the two types. Conclusion Seal ring type cystic lung cancer is a special type of cystic lung cancer. Its morphological manifestation is related to tumor invasive growth and usually indicates tumor progression.

Key words: lung cancer, cystic, CT, pathology