The Football Sign: An Alarming Feature on Supine Radiograph.

Football sign is a rare radiographic finding on abdominal x-ray that suggests massive pneumoperitoneum. Free air outlines the abdominal cavity and falciform ligament which creates the radiolucent oval contour of a football. Football sign is hardly reported in older children or adults. We present the first clear image of football sign caused by gastric perforation in an adult patient. A 57-year-old male with a history of hepatocellular carcinoma was diagnosed with an undrainable liver abscess and partial gastric outlet obstruction. He developed acute onset of severe abdominal pain afterward and abdominal plain film showed a large oval radiolucency over the central part of the abdomen without interruption by intestine, a classical finding of pneumoperitoneum also known as a "football sign". Emergent laparotomy revealed a 0.5 cm perforation hole at the anterior surface of the gastric antrum. Despite timely intervention, the patient died from progression of multiorgan failure. This case describes an alarming radiographic finding that rarely occurs in the adult population. Air could be identified on x-ray in this patient due to presence of massive ascites in his abdominal cavity. Recognizing radiographic patterns that suggest pneumoperitoneum on supine plain radiographs could expedite the diagnostic process and surgical intervention.