Not All Painless Jaundice in the Elderly Is Primary Pancreatic Cancer.

Painless jaundice in elderly patients typically suggests primary pancreaticobiliary malignancy, but metastatic disease to the periampullary region represents an uncommon yet important differential diagnosis that can present with identical clinical features. We present a case of a 65-year-old woman with a history of Stage IIIB endometrial adenocarcinoma with known pelvic and mesenteric metastases, previously treated with salvage chemotherapy, who presented with 3 days of progressive painless jaundice, dark urine, and a year-long history of worsening diarrhea with significant weight loss. Laboratory evaluation revealed a cholestatic pattern of liver injury (total bilirubin 8.1 mg/dL and alkaline phosphatase 862 U/L), and imaging demonstrated new intra- and extrahepatic biliary ductal dilation with a spiculated duodenal mass infiltrating the ampulla and pancreatic head, along with bilateral hydroureteronephrosis from pelvic disease. Endoscopic retrograde cholangiopancreatography confirmed an infiltrative ampullary mass with successful biliary stent placement for decompression, resulting in improvement of hyperbilirubinemia. This case demonstrates that metastatic endometrial carcinoma can present as painless obstructive jaundice through duodenal and ampullary involvement, closely mimicking primary pancreatic adenocarcinoma both clinically and radiographically. Recognition of atypical metastatic patterns is essential for appropriate oncologic management, as treatment strategies and prognosis differ significantly between primary pancreaticobiliary malignancy and metastatic disease.