Solid to cystic: A case report of imaging findings of atypical lung metastases

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.