Question: What code would I use for an excision of a retro hepatic mass via thoracic-abdominal incision? California Subscriber Answer: You should consider the liver to be an intraperitoneal organ. Therefore, look at the following codes to see which best describes the procedure your physician performed: 49203 -- Excision or destruction, open, intra-abdominal tumors, cysts or endometriomas, 1 or more peritoneal, mesenteric, or retroperitoneal primary or secondary tumors; largest tumor 5 cm diameter or less 49204 -- ... largest tumor 5.1-10.0 cm diameter 49205 -- ... largest tumor greater than 10.0 cm diameter.