Abstract
BACKGROUND: Secondary or metastatic tumors of the pancreas are exceedingly rare. This study aims to elucidate an uncommon etiology contributing to pancreatic masses: extramedullary plasmacytoma. CASE REPORT: A 77-year-old male patient, undergoing treatment for multiple myeloma, presented with jaundice and abdominal pain. Laboratory findings indicated cholestasis. Imaging techniques revealed a dilated biliary tree and a hypoechoic mass in the head of the pancreas. Endoscopic examination showed significant narrowing of the duodenal lumen with an infiltrative pattern in the duodenal wall. Biopsies were taken from the narrowed area, and percutaneous biliary drainage was performed in the radiology department. Histopathological analysis of the biopsies revealed features consistent with plasmacytoma, characterized by infiltration with atypical plasma cells and positivity for CD138 in immunohistochemistry. CONCLUSION: In cases where a patient with multiple myeloma presents with a pancreatic mass, it is imperative to consider the possibility of a pancreatic plasmacytoma as a potential diagnosis.