Primary bile duct CD20-negative B cell lymphoma presenting as cholestatic jaundice in a patient with HIV

Primary bile duct lymphoma is an exceptionally rare cause of biliary obstruction and may mimic cholangiocarcinoma or AIDS cholangiopathy on imaging particularly in immunocompromised patients. We report a man in his 30s with a newly diagnosed HIV infection (CD4 count 153 cells/µL) who presented with progressive jaundice, weight loss, fever and abdominal pain. Initial laboratory investigations revealed a cholestatic pattern of liver injury. Imaging demonstrated diffuse biliary strictures, infiltrative lesions and a hypovascular mass, initially suggestive of cholangiocarcinoma or sclerosing cholangitis. Endoscopic ultrasound-guided fine-needle aspiration and brush cytology revealed a CD20-negative, PAX5+/CD79a+B cell lymphoma. The patient was treated with antiretroviral therapy and CHOP-based chemotherapy with intrathecal therapy, resulting in rapid clinical improvement. This case highlights the diagnostic challenge of biliary obstruction in advanced HIV and underscores the importance of tissue diagnosis in distinguishing lymphoma from infection or other malignancies.