A 74-year-old man with long-term primary sclerosing cholangitis and ulcerative colitis had a soft-tissue mass in the gallbladder that was detected during a semiannual magnetic resonance imaging surveillance examination in March 2006. That study (Figure A; coronal enhanced fat-suppressed, T1-weighted image) revealed uniform enhancement in the thickened gallbladder wall (long arrow), and mild dilatation of the intrahepatic ducts (small arrows) with more central effacement indicated underlying primary sclerosing cholangitis. Serum hepatobiliary tumor marker levels for α-fetoprotein, carbohydrate antigen 19-9, and carcinoembryonic antigen all were within the normal range. Regional lymph nodes appeared clinically normal during open cholecystectomy, and the patient had no ascites. The gallbladder measured 4.5 × 4.0 cm and contained multiple gallstones. The gallbladder wall was 0.8 cm thick and contained compact aggregates of morphologically abnormal, nonpolarized lymphoid follicles that permeated the wall of the gallbladder (Figure B; H&E: original magnification, 20×). The lymphoid follicles and extrafollicular lymphocytes were positive for CD10 (Figure C; CD10 immunostain: original magnification, 100×), CD20, and BCL-6, indicating a follicular center cell origin. The lack of germinal center BCL-2 oncoprotein expression (often negative in extranodal follicular lymphomas) and the lack of BCL-2–immunoglobulin H fusion with the presence of B-cell clones (detected by polymerase chain reaction for immunoglobulin H gene rearrangement) were consistent with a B-cell lymphoma of extranodal origin. No lymphocytic or plasma cell periportal infiltrates were identified to suggest autoimmune cholangitis, and the liver biopsy findings were most consistent with biliary cirrhosis.

FOR FULL TEXT (PDF version). Please click here.