The imaging spectrum of pulmonary metastases varies greatly, with solid and partly cavitating nodules being the most common. When imaging the oncology patient, specifically follow-up imaging post-treatment, the radiological aim is to assess for disease regression and thus treatment response, usually with resolution of these nodules. We report an interesting case series of a patient with primary endometrial carcinoma presenting with pulmonary metastases. This imaging series eloquently depicts the temporal evolution of the metastatic solid pulmonary nodules to cavitating nodules and finally to thin-walled cysts. Baseline imaging in this scenario is vital to exclude pre-existing cystic lung disease. The progression of solid pulmonary metastases to simple cysts is an uncommon therapy-related consequence, but an important entity to recognise, not only as an indicator of good treatment response, but also to evaluate for potential life-threatening complications such as spontaneous pneumothoraces.