S3210 Pancreatic Metastasis From Endometrial Carcinoma Presenting as a Diagnostic Challenge: A Case Report

Introduction: Pancreatic metastases from distant primary tumors are uncommon, with endometrial carcinoma being a rare origin. Such metastases can present with non-specific abdominal symptoms, often mimicking primary pancreatic neoplasms or pancreatitis, posing a diagnostic challenge. Accurate diagnosis, typically requiring advanced imaging and histopathological confirmation via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), is crucial for appropriate management. Case Description/Methods: A 74-year-old woman with a history of surgically treated endometrial carcinoma, under routine oncologic surveillance, developed diffuse, severe abdominal pain radiating to the back. Initial workup, including labs and imaging, was inconclusive, though acute pancreatitis was considered. CA 19-9 was mildly elevated (67 U/mL). Subsequent imaging revealed a hypodense, irregularly marginated solid lesion in the pancreatic uncinate process, posterior to the superior mesenteric artery/superior mesenteric vein, showing interval enlargement. EUS demonstrated a 29 × 25 mm hypoechoic lesion in the same region, without regional lymphadenopathy. EUS-FNA provided adequate tissue for cytology. Histopathology confirmed metastatic endometrial carcinoma involving the pancreas. Multidisciplinary review recommended 4 to 6 cycles of systemic chemotherapy. Discussion: This case highlights metastatic endometrial carcinoma presenting as a solitary pancreatic lesion, initially a diagnostic dilemma with pancreatitis as a differential. Symptom progression and lesion enlargement prompted further investigation. EUS-FNA was instrumental in obtaining tissue for histopathological diagnosis, differentiating the metastasis from primary pancreatic malignancy. This report underscores considering pancreatic metastatic disease, even from rare primaries like the endometrium, in cancer patients with new pancreatic findings. A multidisciplinary approach is essential for diagnosis and determining optimal oncologic management, here systemic chemotherapy.