Abstract
INTRODUCTION: Primary lymphoma of the ampulla of Vater is an exceptionally rare entity, with most reported cases being low-grade B-cell lymphomas in adults. Diffuse large B-cell lymphoma (DLBCL) at this site is markedly aggressive and exceedingly uncommon in the pediatric population. CASE PRESENTATION: An 11-year-old male presented with obstructive jaundice. Abdominal ultrasound revealed a dilated gallbladder. Endoscopic retrograde cholangiopancreatography (ERCP) identified a fungating mass at the ampulla of Vater, causing significant biliary dilation. Histopathological and immunohistochemical analysis of biopsy samples (positive for leukocyte common antigen and CD20, negative for CD3) confirmed the diagnosis of DLBCL. Staging CT scan showed localized disease with cervical lymphadenopathy. The patient was managed with biliary stenting and systemic immunochemotherapy (R-COP protocol). Following an episode of hepatotoxicity, doxorubicin was introduced. Posttreatment imaging showed an excellent therapeutic response, and the patient was scheduled for consolidative radiotherapy. CONCLUSION: This case underscores that lymphoma, though rare, should be considered in the differential diagnosis of obstructive jaundice even in children. A multimodal approach involving ERCP with biopsy and imperative immunohistochemistry is crucial for an accurate diagnosis to avoid unnecessary surgery. Management centered on immunochemotherapy, with adjuncts like biliary decompression and radiotherapy, can lead to successful outcomes in pediatric ampullary DLBCL.