A 41-year-old female NF1 patient was admitted for the evaluation of a 3-year history of recurrent epigastric soreness, heartburn, and diarrhea. Repeated endoscopic examinations revealed recurrent duodenal ulcers. The symptoms were relieved by proton-pump inhibitors, but recurred when the medication was withdrawn. She was previously diagnosed with NF1 based on clinical features and family history. Her first-degree relatives (i.e., brother, sister, and second son) were also affected by fully developed features of NF1. She had no cognitive dysfunction or learning disabilities, and showed normal intellectual development. A physical examination revealed several cafe-au-lait spots and multiple small nodules on the anterior chest and areolar area, and also multiple axillary freckles. A skin-nodule biopsy demonstrated characteristic neurofibromas.
On admission, upper gastrointestinal endoscopy revealed multiple shallow ulcers in the descending duodenum. The rapid urease test and urea breath test for Helicobacter pylori were both negative. The serum fasting gastrin level was >1,000 pg/mL and 837 pg/mL in two consecutive measurements. A secretin stimulation test was not performed due to the unavailability of secretin. As a diagnosis of gastrinoma was strongly suggested, radiologic evaluations were performed to locate the lesion. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) scans showed a 3 x 2-cm, clearly defined, well-enhanced mass adjacent to the duodenal loop in the subhepatic space (Figure 1). No metastatic lesions were observed in the liver or regional lymph nodes.
The association with MEN1 status was evaluated by hormonal and radiologic investigations of the parathyroid, pituitary, pancreas, and adrenal gland, which proved to be negative. As a definitive treatment, an intraabdominal mass of about 2.5 x 2 cm with a thick fibrous capsular outer layer was surgically isolated and completely resected from the right lateral border of the descending duodenum. Gastrinoma was finally diagnosed by immunohistochemical staining (Figures 2, 3). An incidental finding during the operation was numerous, small (<1.0 cm), whitish nodular masses on the serosal surface of the small bowel, many of which were enucleated. The pathologic diagnosis was gastrointestinal stromal tumor (GIST) with a low mitotic index as evidenced by C-kit positivity (Figures 4, 5). The serum gastrin level decreased markedly to 99.1 pg/mL at 1 month after the operation, and to 53.2 pg/mL 3 months later. There were no symptomatic or radiologic recurrences during a 14-month follow up.