Clinicopathological and CT Findings of Cystic Lung Cancer

Objective: Cystic lung cancer is a rare type of lung cancer with special morphological manifestations on imaging that have not been completely recognized. This study aimed to improve the understanding and diagnosis of this lung cancer by analyzing its computed tomography (CT) features and clinicopathological findings. Methods: The clinical data, pathological types, and CT features of patients with cystic lung cancer who were diagnosed at our hospital between January 2015 and June 2021 were analyzed retrospectively. Results: We identified 44 cases (86.27%) of adenocarcinomas; these included 7 (13.73%) and 35 (68.63%) cases of microinvasive adenocarcinomas and invasive adenocarcinomas, respectively. Regarding the histological type, 11 (21.57%), 8 (15.69%), and 15 (29.41%) cases were of the adjoint, papillary, and acinar types, respectively. Two cases (3.92%) contained micropapillary components that accounted for more than 20% . Furthermore, one case (1.96%) was not classified, and in another case (1.96%), pathological examination after chemotherapy suggested an adenocarcinoma. Lymph node biopsy in one case (1.96%) suggested a metastatic lung adenocarcinoma. Squamous cell carcinoma was observed in five cases (9.80%); these included three (5.89%) and two (3.92%) cases of keratinizing and non-keratinizing squamous cell carcinomas, respectively. A large cell carcinoma and a high-grade mucoepidermoid carcinoma were observed in one case each (1.96%). A peripheral distribution was observed in 40 cases (80.30%). The mean diameter was 4.7± 2.7 cm. A cystic cavity with ground glass, cystic cavity with solid components, and cystic cavity with mixed components were observed in 20 (39.22%), 22 (43.14%), and 9 (17.65%) cases, respectively. According to the Mario classification, 24 (47.06%), 8 (15.69%), 9 (17.65%), and 10 (19.61%) cases were of types I, II, III, and IV, respectively. The cyst wall was uneven in 42 cases (82.35%); furthermore, a lobular lesion edge and the burr sign were observed in 28 (54.90%) and 14 (27.45%) cases, respectively. Moreover, 33 cases (64.71%) showed a separation within the lesions, while 36 cases (70.59%) had a smooth inner lesion wall. Regarding the relationship with the pleura, pleural traction and closed pleura were observed in 24 (47.06%) and 11 (21.57%) cases, respectively. The peripheral blood vessels passed through the lesion in eight cases (15.69%) and adhered closely to the edge of the lesion in 16 cases (31.37%). The surrounding bronchi passed through the lesion in eight cases (15.69%) and moved toward the edge of the lesion in 21 cases (41.18%). Conclusion: Cystic lung cancer has certain features on CT that can allow its suggestive diagnosis.