We report the case of a 9-year-old child with asthma, atopic dermatitis and allergic rhinoconjunctivitis due to house dust mites, in whom a routine chest x-ray identified by chance abnormal organ position, such as the stomach located on the right side. Abdominal ultrasonography indicated a centralised liver, with polysplenia on the right side and an inferior cava vein located to the left of the aorta with no interruption. Ultrasonography did not show heart defects. Magnetic resonance imaging (MRI) of the abdomen was performed that showed a short pancreas, with no neck, body and tail in it, and a left inferior vena cava with normal outlet of the renal veins, and absence of the intrahepatic part of the inferior vena cava, that was replaced by the left hemiazygos vein. Spinal cord MRI revealed dorsal syringomelia. In view of the results obtained, the diagnosis of situs ambiguous was established.