The article reports on a 60-year-old female patient with insulin-dependent diabetes who presented with coughing, chest pains and low-grade fever. Auscultation revealed a vesicular breathing noise bilaterally and the laboratory results showed slightly increased infection parameters. The initial diagnostic work-up included chest x-ray and contrast-enhanced computed tomography (CT). The diagnostics resulted in a pulmonary adenocarcinoma with osseous and hepatic metastases. Furthermore, widespread bilateral pulmonary cystic lesions were observed. Regarding the wide spectrum of differential diagnoses and the clinical pattern, the findings have to be regarded as cystic metastases and not as primary cystic lung disease.