Gallstones migrating into the right hemithorax post complicated cholecystectomy may be misdiagnosed for lung cancer, especially in the context of a distant history of cholecystectomy, poor recall of medical history and incomplete patient data. We present a case of a female patient with heavy smoking history who presented to our emergency department with haemoptysis and mild weight loss. Imaging workup showed an 18F-fludeoxyglucose positron emission tomography-positive heterogeneous nodule with central calcification in the right lower lobe, carrying lung cancer as a differential diagnosis. The resected specimen revealed an inflammatory pseudomass formed around a gallstone. This case illustrates the importance of knowing the spectrum of clinical and radiological presentation of a gallstone migrating into the right hemithorax, in order to prompt appropriate management and prevent misdiagnosis and mistreatment.