Duodenal adenoma-neuroendocrine combined tumor of the duodenum: not a usual duodenal polyp

Document Type

Conference Proceeding

Publication Date


Publication Title

Am J Gastroenterol


Introduction: A composite intestinal adenoma and carcinoid is a rare intestinal neoplasm consisting of intermingled adenomatous and well-differentiated neuroendocrine (NE) components. Case Description/Methods: A previously healthy 50-year-old female was referred to our institution for evaluation and treatment of a large duodenal polyp which was found incidentally during the diagnostic evaluation of persistent diarrhea and abdominal pain. An esophagogastroduodenoscopy (EGD) showed a large and lateral spreading tumor extending approximately 75% of the circumference of the descending duodenum (Figure 1A). Biopsies showed tubular adenoma with no dysplasia. Endoscopic ultrasound showed a soft tissue growth at the major ampulla with no evidence of wall invasion or intraductal growth (Figure 1B). Colonoscopy showed a circumferential and partially occluding mass at the rectosigmoid junction, 17 cm from anal verge. Biopsies showed a tubulo-villous adenoma with high grade dysplasia. However, a repeated biopsy confirmed an invasive adenocarcinoma. Further imaging showed no evidence of distant metastasis. A repeated EGD and endoscopic retrograde cholangiopancreatography was performed with a major papillectomy using hot snare endoscopic mucosal resection (EMR) and an extensive piecemeal cold snare EMR of the rest of the polyp. The pancreatic duct and the bile duct were accessed, a biliary sphincterotomy was performed, and a pancreatic duct plastic stent was inserted to decrease the risk of post-ERCP pancreatitis (Figure 2). The pathological review of the resected tissue showed a duodenal tubular adenoma with a well-differentiated NET which was positive for chromogranin A (Cg-A) and synaptophysin. A repeated procedure in 4 weeks showed a normal appearing duodenal scar with no evidence of residual tissue (Figure 3). The patient underwent neoadjuvant chemoradiation for the colon cancer with a scheduled robot-assisted resection of the colon and rectum. Discussion: Although localized endocrine cell differentiation in benign or malignant gastrointestinal glandular neoplasms is relatively common, truly mixed glandular-endocrine neoplasms are rare. In regards to treatment, if the NET is confined to the mucosa without angioinvasion (WHO class I), treatment consists of polypectomy with clear margins, as in our case. Due to the rarity of this entity, awareness and attention to the cytologic features are crucial, and IHC staining is essential and helpful in delineating the NE component.

PubMed ID

Not assigned.





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