Figure 12b. Fetus in fetu. (a) Axial contrast material-enhanced CT image of an infant shows a large abdominal mass containing fat, fluid, and calcifications resembling vertebrae (arrow). (b) Photograph of the cut surface of the gross specimen shows a well-developed spine, which contained elements of a spinal cord. Other tissues identified were portions of a gastrointestinal tract, cartilage, bone, and bone marrow. All elements were histologically mature.