Hilar malignancy: treatment with an expandable metallic transhepatic biliary stent. An expandable metallic transhepatic biliary endoprosthesis was used to treat 20 patients with hilar malignancy and isolated right and left intrahepatic ducts. In 12 patients, only one intrahepatic ductal system was drained; in eight patients, both systems were drained. In five patients, both systems were drained through a single transhepatic track by arrangement of two stents in a T configuration. The initial technical success rate in placing the stents and achieving internal drainage was 100%. Complications necessitating further intervention occurred in two of the 20 patients. Short-term clinical follow-up was available for 19 of the 20 patients. Two months after stent insertion, two patients complained of persistent jaundice, two patients died without jaundice, and 15 patients were free of symptoms of biliary obstruction. A variety of geometric configurations are possible with this endoprosthesis. The relative merits of these stent arrangements are discussed, and a new technique for placing the stents in a T configuration is described. 