大澤 英之

Gastric cancer is a common malignancy and remains potentially lethal. The prognosis of patients with stage IV gastric cancer is thought to be poor, but new molecular targeted therapy may benefit patients with advanced gastric cancer. Currently, conversion surgery after chemotherapy with a trastuzumab-containing regimen is reported to be effective in these patients. We present 3 patients with human epidermal growth factor receptor 2 (HER2)–positive advanced gastric cancer who underwent conversion surgery after receiving a trastuzumab-containing chemotherapy regimen. Interestingly, the primary lesion acquired resistance to the trastuzumab-containing regimen, although the metastatic lesions maintained a complete response. The reason why the primary lesions became resistant to trastuzumab remains unclear. More studies are needed to clarify the mechanism of resistance. Conversion surgery, made possible by the use of molecular-targeted therapy, may improve the prognosis of patients with stage IV gastric cancer, particularly if metastatic lesions show a complete response to therapy.

We report a rare case of immunoglobulin G4 (IgG4)-related sclerosing cholangitis without other organ involvement. A 69-year-old-man was referred for the evaluation of jaundice. Computed tomography revealed thickening of the bile duct wall, compressing the right portal vein. Endoscopic retrograde cholangiopancreatography showed a lesion extending from the proximal confluence of the common bile duct to the left and right hepatic ducts. Intraductal ultrasonography showed a bile duct mass invading the portal vein. Hilar bile duct cancer was initially diagnosed and percutaneous transhepatic portal vein embolization was performed, preceding a planned right hepatectomy. Strictures persisted despite steroid therapy. Therefore, partial resection of the common bile duct following choledochojejunostomy was performed. Histologic examination showed diffuse and severe lymphoplasmacytic infiltration, and abundant plasma cells, which stained positive for anti-IgG4 antibody. The final diagnosis was IgG4 sclerosing cholangitis. Types 3 and 4 IgG4 sclerosing cholangitis remains a challenge to differentiate from cholangiocarcinoma. A histopathologic diagnosis obtained with a less invasive approach avoided unnecessary hepatectomy.