The use of preoperative pneumoperitoneum was described initially for the repair of large ventral hernias. Large volumes of air are injected into the peritoneal cavity, which distends the abdominal wall progressively. This method is usually used to facilitate the reinstatement of the viscera into the abdominal cavity and improves postoperative diaphragmatic function. The authors use this method for preoperative tissue expansion of the abdominal wall before full-thickness resection of the abdominal wall for dermatofibrosarcoma protuberans in a 12-year-old girl. In total, 6.8 L air was injected over 3 weeks without problem. The subsequent laxity of the abdominal wall permitted the primary closure of a 14- x 16-cm resection. The postoperative course was uncomplicated. Preoperative pneumoperitoneum can be used when reconstruction can be delayed. This is so in cases of slow tumor growth and in cases of infectious or posttraumatic full-thickness abdominal defects. The parietal laxity obtained with the pneumoperitoneum not only increases the possibilities of direct closure but also increases the possibilities of pedicled flap reconstructions.