P1985 - Double Trouble: The Rectal Polyp Hiding a Tubulovillous Adenoma and a Carcinoid Surprise

Abdulazeez Swaiti, MD¹, Jinye Liu, DO², Michelle Cooley, BS³, Matthew Tugman, BA³, Catherine Gray, BS³, Stephanie Ibarra Lepe, MD², Christin Wilkinson, MD¹, Ahmed Hebishy, MD², Saeed Graham, MD¹, Christina Santana, MD², Amy Chang, MD², Hassam Ali, MD¹, Zarak Khan, MD⁴, Rahul Pamarthy, MD¹, Kara Regan, MD^4
1East Carolina University, Greenville, NC; ²East Carolina University Medical Center, Greenville, NC; ³East Carolina University Brody School of Medicine, Greenville, NC; ⁴East Carolina Gastroenterology, Greenville, NC

Introduction: Neuroendocrine tumors (NETs) are neoplasms originating from neuroendocrine cells found throughout the body, with the gastrointestinal tract (GIT) accounting for 60% of primary tumors. Although NETs can present with the classic syndrome mnemonic BeFDR (bronchospasms, flushing, diarrhea, right-sided heart failure from valve lesions), GIT NETs are less likely to manifest with carcinoid syndrome.

The coexistence of carcinoid tumors and tubular adenomas, particularly tubulovillous adenomas, is rarely reported, with only a few case reports. Here, we present a case of a patient with a concurrent carcinoid tumor and tubulovillous adenoma, discussing his presentation, risk factors, and the clinical significance of this diagnosis.

Case Description/Methods: A 61-year-old male with a history of papillary thyroid carcinoma post-total thyroidectomy underwent a screening colonoscopy in clinic. He reported no gastrointestinal symptoms at the time. His colonoscopy revealed a semi-pedunculated polyp at the rectosigmoid junction and a 35-mm polyp in the rectum above the dentate line, classified as Paris 1s. Mucosal resection was performed, and the specimen was biopsied. Pathological examination identified the rectal polyp as a tubulovillous adenoma with a carcinoid tumor in its submucosa. An 18-month follow-up colonoscopy revealed a 10-mm polyp regrowth at the previous scar site, which was resected and biopsied; its margins were treated with a hot snare. The regrowth was a tubulovillous adenoma without a carcinoid tumor in the submucosa.

Discussion: NETs arise from neuroendocrine cells present in various organ systems, capable of receiving nervous system messages and synthesizing and secreting monoamines, peptides, and hormones. The clinical presentation of NETs varies by location, with colonic NETs typically presenting with bleeding, abdominal pain, changes in bowel habits, and weight loss. Risk factors for NETs include a family history of cancer and, specifically for gastric NETs, a long-term history of diabetes. Although colonic NETs are rare, they are often discovered incidentally during screening colonoscopies, as in our patient’s case. The concomitant tubulovillous adenoma finding has been mentioned in the literature as being associated with well-differentiated neuroendocrine tumors, and emphasizes the need for careful pathological evaluation.



Disclosures:


Abdulazeez Swaiti, MD¹, Jinye Liu, DO², Michelle Cooley, BS³, Matthew Tugman, BA³, Catherine Gray, BS³, Stephanie Ibarra Lepe, MD², Christin Wilkinson, MD¹, Ahmed Hebishy, MD², Saeed Graham, MD¹, Christina Santana, MD², Amy Chang, MD², Hassam Ali, MD¹, Zarak Khan, MD⁴, Rahul Pamarthy, MD¹, Kara Regan, MD⁴. P1985 - Double Trouble: The Rectal Polyp Hiding a Tubulovillous Adenoma and a Carcinoid Surprise, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.