S3467 Primary Duodenal Adenocarcinoma: A Rare Malignancy

Abstract

Introduction: Primary duodenal adenocarcinoma (PDA) is extremely rare, representing 0.3 – 1% of all gastrointestinal malignancies. It poses a significant challenge to the physicians due to late non-specific symptoms that delays the diagnosis. Surgical resection is the only treatment option although PDA with distant or nodal metastasis have a very poor prognosis. Case Description/Methods: A 33-year-old male patient presented with epigastric abdominal pain, nausea, vomiting, lipase > 2000, elevated LFTs and hyperbilirubinemia, consistent with acute pancreatitis. CT abdomen and pelvis revealed an irregular mass in the second and third portion of the duodenum near ampulla, dilation of pancreatic and common bile duct along with multiple hepatic lesions, consistent with metastatic malignancy. EGD showed non bleeding duodenal ulcer along with enlarged lymph nodes in the peripancreatic region. Biopsy of the ulcer was suggestive of moderately differentiated invasive duodenal adenocarcinoma with background of high-grade dysplasia. Due to metastatic malignancy, patient was started on folinic acid, fluorouracil and oxaliplatin without undergoing surgery. Percutaneous biliary drain was placed with resolution of pancreatitis and hyperbilirubinemia. Patient also completed a course of antibiotics due to pseudomonas bacteremia and sepsis secondary to pancreatic phlegmon that was drained. Pain was management with fentanyl patch and oral opioids. Patient was later discharged home with outpatient follow up. Discussion: This case highlights the importance of primary duodenal adenocarcinoma (PDA) which is a very rare malignancy. Its etiology is unknown, however patients with familial adenomatosis polyposis, Peutz-Jeghers syndrome, Crohn’s and celiac disease are at higher risk. Due to non-specific symptoms including anorexia, postprandial fullness, nausea, vomiting, jaundice and abdominal pain, early diagnosis is a challenge for physicians. PDA is most commonly seen in second part of the duodenum with an incidence of 50 -70%. It can be diagnosed with the help of contrast imaging studies along with EGD and biopsy. Management is usually surgical resection with tumors of the second part of the duodenum, proximal and distal infiltrating tumors requiring pancreaticoduodenectomy to ensure radical resection. Lymphovascular invasion, lymph node metastasis and perineural invasion are features associated with poor prognosis and high mortality. For unresectable tumors, palliative surgery or endoscopic treatment is usually indicated.