Squamous lung carcinoma associated with thin-wall cavitary lesions that presented with recurrent pneumothorax

Abstract

A 70-year-old man was referred to our department due to left pneumothorax associated with a thin-wall cavitary lesion in the S³ segment of the left lung. Surgical resection of the cavitary lesion was performed, which incidentally detected the development of squamous cell carcinoma around the cavity. Four and 7 months after the surgery, computed tomography (CT) of the chest revealed the development of thin-wall cavitary lung lesions associated with recurrent pneumothorax and the surgical specimens were also found to be composed of squamous carcinoma tissues around the cavities. CT before the third surgery revealed multiple intrapulmonary and hepatic metastatic tumors. As the tumors strongly expressed PD-1, the patient was treated with pembrolizumab, leading to a favorable response. Lung cancer may cause the formation of thin-wall cavities by the check valve mechanism and/or ischemic necrosis. On the other hand, pneumothorax may develop from the check valve mechanism and/or infiltration of carcinoma cells into the pleura. This report suggests that, when an elderly patient with smoking history presents with pneumothorax, the possibility that lung cancer underlies the condition should be considered.