Diffuse Large B-Cell Lymphoma Masquerading as Cholangiocarcinoma in a Young Adult.

A previously healthy 29-year-old man presented with abdominal pain and was found to have a liver mass with periductal infiltration and a stricture of the common bile duct, concerning for cholangiocarcinoma. Hepatic function panel disclosed alanine transaminase 293 U/L, aspartate aminotransferase 122 U/L, γ-glutamyl transferase 2019 U/L, normal total bilirubin, carcinoembryonic antigen, and carbohydrate antigen 19-9. Biopsy established the diagnosis of diffuse large B-cell lymphoma, with no underlying hepatic disease. He was started on polatuzumab-rituximab-cyclophosphamide-doxorubicin-prednisone chemotherapy and achieved complete tumor response. This case highlights the importance of a thorough evaluation of liver tumors and the critical role of tissue diagnosis.