Bile duct MALT lymphoma diagnosed with direct cholangioscopy: a case report.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) extremely rarely arise in extrahepatic biliary tract. Here, we report a case of bile duct MALT lymphoma diagnosed with direct cholangioscopy. The patient was an 80-year-old female with history of esophageal cancer, and had been occasionally treated with balloon dilatation for anastomotic stricture. She was referred to our hospital for treatment of choledocholithiasis. Since transesophageal endoscope insertion was impossible, stone extraction by transjejunal approach was performed. When gastroduodenoscope was directly inserted to the bile duct (direct cholangioscopy), accidentally two flat lesions with development of large atypical vessels in hilar region were noted. Biopsy revealed diffuse infiltration of CD20 positive small- to medium-sized atypical lymphocytes. A diagnosis of bile duct MALT lymphoma was made. The patient underwent eight courses of chemotherapy with rituximab alone, with no evident complications. Although biliary tract MALT lymphoma is rare, advances in cholangioscopy may promote encounter with such lesions. Accumulation of endoscopic figures of biliary tract MALT lymphoma is required.