Si-Young Song

Signet Ring Cell Carcinoma of the Extrahepatic Bile Duct

Most tumors affecting the extrahepatic bile duct are adenocarcinomas; the other histologic types occur only rarely. We herein report the extremely rare case of signet ring cell carcinoma (SRCC) originating from the extrahepatic bile duct. A 55-year-old man was hospitalized for jaundice and pruritus. Computed tomography and positron emission tomography suggested the presence of distal extrahepatic bile-duct cancer. He underwent a pylorus preserving pancreaticoduodenectomy. A histologic study confirmed a signet ring cell neoplasm of the distal common bile duct. Because the upper resection margin was invaded by the tumor, he received postoperative concurrent chemoradiotherapy and four cycles of chemotherapy. The patient has survived with no evidence of recurrence for 2 years. This is the second case of primary SRCC of the distal extrahepatic bile duct reported in the literature; further reports of cases are warranted to determine the nature of SRCC in the extrahepatic bile duct.

Chalcogenide glasses for optical brazing

Protective coatings of CVD diamond have been bonded to infrared-transmitting optical windows of ZnSe with As-Se-S system chalcogenide glasses of which the refractive index is made to closely match that of diamond by the “optical brazing” process. To select optimal composition in the As-Se-S system, the Tg, Ts, reflective index and infrared-transmittance of the glass samples were measured. Measurement of transmittance with a Fourier transform infrared spectrometer after the brazing process confirmed that scattering losses were greatly reduced. Infrared transmittance of ZnSe windows with a thin film diamond coating bonded to chalcogenide glass was about 63%.