The V sign of Naclerio. A one-year-old male, hospitalized with a diagnosis of pneumonia in the lower left lobe, with no satisfactory response to treatment. After the insertion of a nasogastric tube, there was worsening of the clinical status, a chest X-ray showing the V sign of Naclerio and suggesting a diagnosis of esophageal rupture with pneumoperitoneum. Vertical branch (thin arrows) and horizontal branch (thick arrow).