P2648 - A Challenging Diagnosis of Small Bowel Gastrointestinal Stromal Tumor at the Ileocolic Anastomosis

Addis Mekonnen, MD¹, Mudassar Sandozi, DO¹, Ahmet Sakiri, MD¹, Sabah Mahmood, MD¹, Kelly Fan, BS, BA², Thayer Hamoudah, MD¹, Naser Khan, MD¹, Altaf Dawood, MD, MBBS^1
1MercyHealth, Rockford, IL; ²University of Illinois College of Medicine Rockford, Rockford, IL

Introduction: Gastrointestinal stromal tumors (GISTs) are benign, and account for approximately 1-2 percent of total primary gastrointestinal neoplasms. 40-60% are found in the stomach and 25-30% are found in the small intestine. Here we describe a rare case of ileal GIST that occurred at an anastomotic site post-colectomy for colorectal cancer who presented for melena.

Case Description/Methods: A 65-year-old male with CAD s/p CABG, history of adenocarcinoma of the cecum status post right hemicolectomy, HTN, and HLD who presented with melena with generalized weakness. Gastroenterology service was consulted, and EGD/Colonoscopy was performed which was negative for any cause of bleeding. During the same admission, the patient underwent CT abdomen/pelvis which revealed a low right quadrant mass at an anastomotic site measuring 6.2x9.1 cm in size without a local or regional metastasis to the abdomen or pelvis suspected to be a small bowel mass. The patient underwent a CT-guided biopsy which showed a low-grade GIST. The patient was evaluated by general surgery and underwent exploratory laparotomy with resection of the GIST with ileocolonic anastomosis. The patient recovered well, and first-line chemotherapy, a tyrosine kinase inhibitor, was started.

Discussion: Diagnosis of GISTs at anastomotic sites poses a challenge due to a nonspecific clinical presentation, varying appearances on radiologic imaging, and limited range of visualization provided by upper endoscopy and colonoscopy. In the absence of syndromes such as familial GIST, neurofibromatosis 1, and Carney triad, GIST tumors rarely occur in association with other tumors. A broad differential diagnosis including GIST should be considered in evaluating a patient with prior malignancy presenting with non-specific symptoms, negative genetic studies, no residual tumor with pathology studies, and inconclusive imaging studies, preoperative biopsy can aid in confirming the diagnosis.



Disclosures:


Addis Mekonnen, MD¹, Mudassar Sandozi, DO¹, Ahmet Sakiri, MD¹, Sabah Mahmood, MD¹, Kelly Fan, BS, BA², Thayer Hamoudah, MD¹, Naser Khan, MD¹, Altaf Dawood, MD, MBBS¹. P2648 - A Challenging Diagnosis of Small Bowel Gastrointestinal Stromal Tumor at the Ileocolic Anastomosis, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.