S3542 An Uncommon Cause of Abdominal Obstruction: A Jejunal GIST

Introduction: Gastrointestinal Stromal Tumors (GISTs) are rare neoplasm representing only 1% of all primary GI tumors. Yet they are the most common mesenchymal tumor (80%) of the GI tract with an age of onset usually between the seventh decade of life and a similar male-to-female ratio. GISTs can originate at any site from the esophagus to the anus and in fewer cases outside the GI tract. Therefore, having a wide range of presentation from asymptomatic to signs of acute abdomen. We report a case of a jejunal GIST causing chronic obstruction of the small intestine. Case Description/Methods: Case of a 54-year-old male, inmate with medical history of Hepatitis C arrives to the emergency department with complaints of intractable emesis and abdominal discomfort. The patient reports 8-10 episodes/day of gastric content vomiting that eventually turned bilious for the past 2 weeks. Furthermore, he refers having epigastric discomfort associated with fatigue, anorexia, and weight loss of 20 lbs since approximately 2 months ago. The patient denied any family history of gastrointestinal disease. On evaluation, he appeared chronically ill with signs of hypovolemic shock. Physical exam was remarkable for a peri-umbilical mass with no tenderness to palpation. Abdominal CT showed an exophytic soft tissue mass arising from the mid ileum that measured approximately 4.5 × 5.3 × 4.7 cm with associated slight swirling of the mesentery and upstream bowel loops, resulting in transition point and upstream dilatation of the small bowel compatible with a partial high grade small bowel obstruction. He underwent percutaneous biopsy with pathology report resulting in a spindle cell lesion, high risk, most consistent with GIST. Immunohistochemistry was only positive for C-KIT with a mitotic rate > 5/5 mm2. The patient had surgical excision of jejunal mass via small bowel resection and was discharged on tyrosine kinase inhibitor. At 6 months follow up, the patient was found disease free. Discussion: Occasionally, GISTs are found incidentally on imaging, predominantly in the stomach and small intestine, respectively. In our case, the patient presented with a KIT-positive jejunal GIST causing abdominal obstruction. Neoadjuvant therapy with Imatinib was given due to its elevated mitotic rate and high risk for progression. Early detection of these tumors requires a high level of suspicion hence the necessity of additional investigation to improve the prognosis and survival rates in this population.