Stent Insertion in Patients with Malignant Biliary Obstruction: Problems of the Hanaro Stent

PURPOSE: To investigate the problems of the Hanaro stent (Solco Intermed, Seoul, Korea) when used in the palliative treatment of patients with inoperable malignant biliary obstruction. MATERIALS AND METHODS: Between January 2000 and May 2001, the treatment of 46 patients with malignant biliary obstruction involved percutaneous placement of the Hanaro stent. Five patients encountered problems during removal of the stent's introduction system. The causes of obstruction were pancreatic carcinoma (n=2), cholangiocarcinoma (n=2), and gastric carcinoma with biliary invasion (n=1). In one patient, percutaneous transhepatic cholangiography and stent insertion were performed as a one-step procedure, while the others underwent conventional percutaneous transhepatic biliary drainage for at least two days prior to stent insertion. A self-expandable Hanaro stent, 8-10 mm in deameter and 50-100 mm in lengh, and made from a strand of nitinol wire, was used in all cases. RESULTS: Among the five patients who encountered problems, breakage of the olive tip occourred in three, upward displacement of the stent in two, and improper expansion of the distal portion of the stent, unrelated with the obstruction site, in one. The broken olive tip was pushed to the duodenum in two cases and to the peripheral intrahepatic duct in one. Where the stent migrated during withdrawal of its introduction system, an additional stent was inserted. In one case, the migrated stent was positioned near the liver capsule and the drainage catheter could not be removed. CONCLUSION: Although the number of patients in this study was limited, some difficulties were encountered in withdrawing the stent's introduction system. To prevent the occurrence of this unusual complication, the stent should be appropriately expansile, and shape in the olive tip shoud be considered.

CT Finding of Signet Ring Cell Carcinoma of the Stomach

PURPOSE: Signet-ring cell carcinoma is rather invasive and infiltrative than other histologic types of gastric cancer. We evaluated the characteristic CT findings of signet-ring cell carcinoma especially in the intensity and pattern of contrast enhancement. MATERIALS AND METHODS: We analyzed the CT findings of 22 cases with histologically proven signet-ring cell carcinoma, and compared them with those of 35 cases with histologically proven tubular adenocarcinoma. RESULTS: The double ring enhancement of the gastric mass was seen in 12 cases of signet-ring cell carcinoma and only one case of tubular adenocarcinoma. The masses of signet-ring cell carcinoma were enhanced more by the CT number of 10.2 than those of tubular adenocarcinoma. Of the masses of signet-ring cell carcinoma, those showed double ring enhancement were more intensely enhanced than those showed diffuse enhancement by the CT number of 22.9. CONCLUSION: We thought that neovascularity and different infiltration of the tumor cells in the gastric wall were responsible for the intense enhancement and double ring sign of signet-ring cell carcinoma. The possiblity of signet-ring cell carcinoma is high if a gastric mass show double ring sign and strong contrast enhancement.