Diaphragmatic (Bochdalek) hernias simulating pulmonary metastases on computed tomography.

Three patients with known primary malignancy and a normal chest radiograph are presented. Computed tomographic scans viewed on 'lung' settings showed a solitary mass lesion simulating a neoplastic mass in the posterior costophrenic recess in each patient. These lesions in fact were small herniations of abdominal fat into the chest through diaphragmatic defects.