Possible Primary Lymph Node Gastrinoma: Occurrence, Natural History, and Predictive Factors: A Prospective Study

Objective: To analyze the results of a prospective study of 176 patients with Zollinger-Ellison syndrome (ZES) (138 sporadic, 38 MEN1) undergoing 207 operations over a 17-year period. Summary Background Data: The existence of lymph node (LN) primary gastrinoma causing ZES is controversial. Methods: Three groups of patients were compared: LN only resected, cured, and no relapse (likely LN primary); same criteria but relapse (unlikely LN primary); and duodenal primary and LN metastases (Duo-LN). Results: Forty-five (26%) had only LN(s) as the initial tumor found. Twenty-six of the 45 (58%) fit the definition of a likely LN primary because they were apparently cured postresection. At 10. 4 ± 1.2 years, 69% of the 26 patients with likely LN primary tumors have remained cured and have LN primaries. In the 8 of 26 with recurrent ZES, it occurred at 5 ± 1 years, and 3 had duodenal gastrinoma that had been missed. Ten percent (13/138) of all patients with sporadic ZES and 0% (0/38) with ZES and MEN1 remained cured with only a LN tumor removed. In patients with sporadic gastrinomas no clinical, laboratory, or radiographic localization feature differed among patients with likely LN primary (n = 16) and those with unlikely LN primary (n = 6) or those with Duo-LN (n = 37). In the likely LN primary group, the largest LN was 2.2 ± 0.2 cm, the number of LNs removed was 1.3 ± 0.1 (25% ≥1 LN), and 78% were in the gastrinoma triangle, which also did not differ from the other 2 groups. Disease-free survival was similar in the likely LN primary group, patients with Duo-LN, and those with pancreatic primaries. Conclusions: These results support the conclusion that primary LN gastrinomas occur and are not rare (approximately 10% of sporadic cases). These results suggest that a proportion (25%) of these tumors are either multiple or malignant. Because no clinical, laboratory, or tumoral characteristic distinguishes patients with LN primary tumors, all patients with ZES undergoing surgery should have an extensive exploration to exclude duodenal or pancreatic tumors and routine removal of lymph nodes in the gastrinoma triangle.