[Differential computed tomographic diagnosis of cavity-forming space-occupying lesions of the lung]

One hundred cavitating pulmonary foci were examined by CT; the appearances have been analysed and compared with the histological findings. Three types of disease have been characterised: bronchial carcinomas, lung metastases and benign lesions. Compared with benign lesions, malignant disease shows a significantly higher incidence of cystic or multiple cavities: thick cavity walls; radiation of tumour tissue; enlarged mediastinal lymph nodes; ipsilateral displacement of the mediastinum; intrapulmonary satellite foci and infiltration of the thoracic wall. Morphologically, tumours can be most easily distinguished from metastases by their ill-defined outer contours. Non-epidermoid primary lung tumours have a higher incidence of pleural effusions and other pleural reactions than have tumours of other origins. 80% of cavitating lung tumours are squamous cell carcinomas, the remaining 20% consist of adeno- and large cell carcinomas. Small cell carcinomas practically never show cavitation.