Caval foramen hernia masquerading as a thoracic mass.

An 85-year-old woman presented with weight loss and a change in bowel habit over the preceding 3 months. Colonoscopy showed several benignlooking polyps in the transverse colon, which were removed with electrocautery snare. We were alarmed to find a suspicious large right paracardiac mass on her chest radiograph (Fig. 1). The possibility of colonic malignancy with lung metastasis or a lung primary tumour was raised. Contrast computed tomography (CT) revealed a large herniation of abdominal viscera into the right thoracic cavity, with mild compression of the inferior vena cava (IVC) below the right atrium. Oblique coronal CT reconstruction, and an almost identical Hounsfield unit for the herniated viscera and for the liver, confirmed the presence of partial herniation of the left hepatic lobe through the diaphragmatic caval foramen into the chest (Fig. 2). The patient said that she had no history of thoracoabdominal trauma. Pathological examination showed the colonic lesions to be benign hyperplastic polyps and, subsequently, the patient’s bowel symptoms resolved.