A Case of Duodenal Adenocarcinoma versus Pancreatic Ductal Adenocarcinoma Metastasis to the Lower Gastrointestinal Tract 2911

• Published in: The American journal of gastroenterology Vol. 113; no. Supplement; p. S1604
• Main Authors: Multani, Monica L., Luebbert, Elizabeth, Skrove, Jamie L., Sarol, Juan, Sobrado, Javier
• Format: Journal Article
• Language: English
• Published: New York Wolters Kluwer Health Medical Research, Lippincott Williams & Wilkins 01-10-2018
• Subjects: Abdomen; Antigens; Biopsy; Cancer; Gastroenterology; Lymphoma; Metastasis; Pancreatic cancer; Small intestine; Tumors
• ISSN: 0002-9270; 1572-0241
• DOI: 10.14309/00000434-201810001-02910

Pancreatic ductal adenocarcinomas (PDA) and duodenal adenocarcinoma rarely metastasize to the lower GI tract. For small bowel cancers (SBC), the incidence of four large histologic types of cancer in the small intestine including lymphomas, carcinomas, sarcomas, and carcinoid tumors are 1.6, 3.9, 1.2, and 2.9 per million per persons respectively. On the other hand, PDAs rarely metastasize to the lung, peritoneum, and liver. We present a case of an unknown metastasis from either the duodenum or the pancreatic duct to the lower gastrointestinal (GI) tract. A 54 year old male with past medical history of Helicobacter Pylori presented with abdominal pain with vomiting, constipation, and a 60lb weight loss. Physical exam showed distended abdomen and epigastric tenderness to palpation. Laboratory was significant for fecal occult positive, Carcinogenic Embryonic Antigen (5.4). Alpha fetoprotein and Cancer Antigen 19-9 were normal. Imaging including Magnetic Resonance Cholangiopancreatography and Triple Phase Computerized Tomography Scan showed a pancreatic body mass with proximal dilatation of the tail. There was no biliary duct dilatation or gallstones. Findings were highly suggestive of PDA. An esophagogastroduodenoscopy and colonoscopy with duodenal and sigmoid/transverse colon biopsies showed infiltrating adenocarcinoma. The immunohistochemical stain for CK7 was positive and CK20 negative. In analysis of the biopsies, CK7 is often positive in epithelial cells of the kidney, prostate, pancreas, ovary, lung, and breast. CK20 negativity shows that it is likely a GI tumor either primary colonic, pancreatic, or gastric cancers. Because of these markers, it was impossible to determine which of these lesions had spread to the lower GI tract. For SBC, a majority of the malignancies are carcinoid: in one particular study, 37.4% were carcinoid, 36.9%, adenocarcinomas, 8.4%, stromal tumors, and 17.3%, lymphomas. Primary carcinomas of the duodenum could spread via the portal system to the liver, systemically to the lung, or to the lower right colon by way of the ileocecal and inferior mesenteric vessels. For end stage pancreatic cancer, metastasis was found within two or more anatomic sites usually in the lung, peritoneum, and liver. It is still unclear in this case which metastasis occurred: from the PDA to the lower GI tract or from the DA to the lower GI tract. Although rare, both must be on the differential for proper management and treatment.