S2117 The GIST of It: A Rare Presentation of Neurofibromatosis Type I

Abstract

INTRODUCTION: Neurofibromatosis Type 1 (NF1) is an autosomal-dominant disease with an incidence of 1 in 2500–3000 individuals. NF1 confers up to a four-fold increase in overall malignancy risk compared to the general population, and patients are 34 times more likely to develop gastrointestinal stromal tumors (GIST). GIST are rare mesenchymal tumors involving the gastrointestinal tract (GI) and their increased incidence has been associated with the history of NF-1. We present a case of a patient with NF-1 associated with an unusual presentation of GIST. CASE DESCRIPTION/METHODS: 42 years old female with past medical history of NF-1 initially presented to the ED for maroon-colored stools for 2 days. She endorsed infrequent use of ibuprofen with last use being 3 months ago. Initial physical exam was significant for mild hypotension responding to fluid resuscitation, and rectal exam negative for blood. The hemoglobin in the ER was 7.9 g/dL (baseline 11.3 g/dL) with an elevation of BUN: Creatinine ratio (24 mg/dL, 0.65 mg/dL). An EGD was performed which demonstrated mild duodenitis. An ileocolonoscopy was performed and blood clots were in the entire colon including the terminal ileum. No source of active bleeding in the colon seen after extensive suctioning done. The patient underwent a video capsule endoscopy (VCE) and an abdominal CT with contrast. VCE demonstrated a endophytic mass with active bleeding. CT revealed numerous exophytic and endophytic masses with the largest mass at the anterior wall of the ileum measuring 2.4 cm × 2.2 cm, which was noted to have a brisk active arterial bleeding. Surgery was consulted and she underwent emergent exploratory laparotomy with surgical resection of the ileal segment containing the actively bleeding mass. Histopathologic staining was positive for receptor tyrosine kinase (C-KIT) and DOG-1, consistent with GIST. Patient was initiated on imatinib therapy and has remained symptom free. DISCUSSION: Our novel case describes life-threatening GI bleeding from GIST in a patient with NF-1. GISTs are 34 times more common in patients with NF-1. In NF-1 patients presenting with GI bleeding, Small bowel GISTs should be considered as a differential and clinicians must have a low threshold for obtaining abdominal imaging by CT, VCE or nuclear imaging in case endoscopy does not detect the source of GI bleeding. Emergent surgery stands alone as a curative form of therapy for actively bleeding GISTs in patients with NF-1.Figure 1.: CT Abdomen with IV contrast : A lobulated endophytic avidly enhancing mass is identified in the Ileum, which measures approximately 2.4 × 2.2 cm. This lesion demonstrates brisk active arterial bleeding into the intestinal lumen.Figure 2.: CT abdomen with IV contrast: There is a round partially exophytic avidly enhancing mass measuring approximately 1.6 × 1.5 cm in the 4th portion of the duodenum, favored to represent a GIST. This lesion is without evidence of active bleeding on the current exam.Figure 3.: Capsule endoscopy – Brisk active bleeding lesion noted on the capsule endoscopy.