Images in Radiology - Foetus in Fetu

A 2-year-old boy presented with gradual distension of the abdomen with an abdominal lump and 2-3 episodes of vomiting. There was history of low-grade intermittent fever. On examination the swelling was firm, ill-defined, globular, non-tender and moved with the respiration. Plain radiograph of the abdomen revealed a well defined mass of approximately 6 cm X 5 cm size, with a definite irregular hyperdense lesion in the right hypochondrium, displacing the bowel loops and the stomach. Ultrasonography (USG) of the abdomen showed a mixed echogenic predominantly cystic areas with large calcific foci causing posterior shadowing. Plain and contrast enhanced computed tomography (CT) scan of the abdomen revealed a 10 cm X 8 cm X 8cms sized mixed density mass with few well-defined cystic lesions within. The wall of the cyst measured 2 to 3 millimeters. There was a well-defined calcified structure within one of the cyst, which resembled the vertebral body (Figure 1). This hyperdense structure was surrounded by fat density (Figure 2). The mass lesion was displacing the bowel loops and was situated anterior to the dorso lumbar spine, extending from the level of upper pole of the kidneys upto the level of anterior superior iliac spine. Rest of the abdominal viscera was unremarkable.