S5988 When Diarrhea Persists: An Unusual Presentation of Terminal Ileum Carcinoid Tumor

Introduction: Carcinoid tumors are rare gastrointestinal neuroendocrine neoplasms with typically indolent progression. Their indolent progression and unspecific symptoms often lead to delayed diagnosis and incidental finding during surgery or imaging. Case Description/Methods: This is the case of a 55-year-old man with a previous history of Fournier gangrene resulting in diverting colostomy, who presented to our institution with a 2-month history of anorexia, nausea, and persistent watery diarrhea resulting in dehydration and acute renal failure requiring multiple emergency department visits. A physical exam revealed a large amount of watery diarrhea on the colostomy bag. Laboratories were remarkable for impaired renal function, normal liver function tests, hypoalbuminemia, and stable normocytic anemia. Stool workup was found to be negative, including culture, Clostridioides difficile toxin, fecal leukocytes, ova and parasites, and Giardia. He was treated symptomatically with loperamide and with aggressive intravenous hydration. Abdomen and pelvis computed tomography with intravenous and by mouth contrast revealed a large intraluminal filling defect extending throughout the ascending colon and thickening of the bowel walls of the distal ileum; findings concerning malignancy. Colonoscopy via stoma was performed and found remarkable for a large exophytic, friable, erythematous, irregular mass at the terminal ileum occluding more than 50% of the lumen and precluding further advancement of the scope. Biopsies showed a well-differentiated neuroendocrine tumor; immunohistochemistry was found to be chromogranin and synaptophysin positive, diffuse, and strong. Additionally, with a ki67 labeling index of less than 2 percent. Further imaging for staging purposes was consequently performed and no evidence of metastatic disease was found. General surgery was consulted and ileocecectomy with primary anastomosis and colostomy takedown was planned, however, the patient had a prolonged hospitalization complicated with multiple nosocomial infections leading to marked clinical deterioration and ultimately to his death. Discussion: Although carcinoid tumors are rare, they can present as persistent chronic diarrhea, often leading to misdiagnosis. Due to their uncommon nature clinicians must maintain a high index of suspicion as thinking beyond the usual suspects of chronic diarrhea can make the difference between delayed discovery and early, life-changing treatment.