S5524 When the Liver Lies: A Rare Presentation of Primary Hepatic Gastrinoma

Introduction: Zollinger-Ellison Syndrome (ZES) is caused by gastrin-secreting neuroendocrine tumors most commonly originating in the pancreas or duodenum. The liver is a frequent site of metastasis, but primary hepatic gastrinomas are exceedingly rare, with fewer than 30 cases reported. Distinguishing primary hepatic gastrinoma from metastatic disease is critical, as complete surgical resection can be curative. Case Description/Methods: A 34-year-old woman with no significant past medical history presented with right upper quadrant abdominal pain that began the night prior. Pain did not radiate to the shoulders or back and had no clear food-related triggers. She denied fever, chills, constipation, diarrhea, or any history of abdominal surgeries. Abd ultrasound showed a 9.8 × 6.5 cm solid lesion in the right hepatic lobe. Computed tomography showed a heterogeneously enhancing mass in the same region, concerning a malignant neoplasm. A liver biopsy confirmed a well-differentiated neuroendocrine tumor, WHO grade 2. Subsequent workup, including EGD, endoscopic ultrasound (EUS), and fine needle aspiration (FNA) biopsies, showed no evidence of a primary lesion in the gastrointestinal tract. Gastrin levels were elevated over 700 pg/mL. Enteroscopy demonstrated scattered erosions throughout the duodenum and proximal jejunum, along with deeper ulcerations and edema in the third part of the duodenum, consistent with ZES. EUS failed to identify a primary tumor, and FNA of peripancreatic lymph nodes was benign. To prepare for surgical resection, the patient underwent right portal vein embolization to promote hypertrophy of the left liver. She then underwent a robotic right hepatectomy to remove the hepatic neuroendocrine tumor. Two months postoperatively, repeat enteroscopy showed healed duodenal ulcers with mild, non-obstructive luminal narrowing and mucosal scarring in the third portion of the duodenum. No active inflammation was observed, and her gastrin levels had normalized. This case represents an extremely rare instance of a primary hepatic neuroendocrine tumor. Discussion: This case highlights an extremely rare presentation of primary hepatic gastrinoma resulting in Zollinger-Ellison syndrome. The absence of an extrahepatic primary tumor despite extensive imaging and endoscopic evaluation, combined with postoperative normalization of gastrin levels and symptom resolution, supports the liver lesion as the primary source. This case emphasizes the importance of a comprehensive diagnostic approach and suggests that, when confirmed, surgical resection can be curative in primary hepatic gastrinoma.