An Unlikely Cause of GI Bleeding: A Rare Clinical Presentation of Gastrointestinal Stromal Tumor

Abstract

Gastrointestinal Stromal tumor (GIST) is a rare mesenchymal tumor of the gastrointestinal tract that can occur at any site between the esophagus and rectum. GIST tumors are usually single, sporadic, and seen in male patients greater than 70 years old. A 32-year-old black lady presented with 1 week history of dizziness, lightheadedness, weakness, and fatigue associated with non-bloody vomiting and two days of hematochezia. Physical exam was significant for heart rate of 100 with blood pressure 103/65mmHg. Additional physical exam findings were benign other than dark red blood noted on digital rectal examination. Laboratory findings were significant for hemoglobin 7.5 mg/dL, hematocrit 24.1%, and platelet 315 k/ul. Additional blood work was unremarkable. Patient received pantoprazole and two units of packed red blood cells. EGD was performed with findings of severe ulcerative esophagitis, normal appearing gastric mucosa with no evidence of fresh or old blood. Fresh blood was noted in distal second portion of the duodenum. Push enteroscopy was then performed with four distinct submucosal masses, pedunculated with central ulceration. They were 1-2 cm each in size and were located between distal second portion and ligament of treitz. Biopsies were taken from each mass and a tattoo was placed distal to the fourth mass.Figure 1Figure 2Figure 3CT scan revealed multiple soft tissue masses predominantly located in mesentery. The largest mass was located medial to the ascending colon (6.6cm x 5.1cm). Colonoscopy was performed with no colorectal masses seen, intubation of terminal ileum to 35cm was notable only for the presence of fresh blood. Histopathology was diagnostic of a CD117 positive, low grade GIST tumor. Patient was started on treatment with imantinib mesylate. GIST tumors are rare mesenchymal tumors of the gastrointestinal tract. They are most commonly diagnosed in men with peak incidence after 70 years of age. The majority of GISTs are found in the stomach (>50%), followed by small bowel (20-30%), colon (2.9%), and rectum (2.7%). GIST tumors are most commonly solitary and sporadic. The presence of multiple primary GIST tumors is rare and previously associated only with pediatric syndromes, familial GIST, Type-1 neurofibromatosis, or Carney's syndrome. Surgical resection is the mainstay of treatment for solitary GIST tumors with use of tyrosine kinase inhibtors such as imantinib mesylate for unresectable or metastatic GIST.