Introduction: Low-grade appendiceal mucinous neoplasm (LAMN) is a rare entity. The clinical implications of disease presentation have not been broadly investigated.
Methods: We included patients with a diagnosis of LAMN, who were assessed at the Mount Sinai Hospital between 2000 and 2018. All cases were reviewed with subsequent exclusion of high grade appendiceal mucinous neoplasms, mucinous adenocarcinomas, and neuroendocrine tumors. We reviewed the impact of patients’ disease presentation on their outcomes.
Results: A total of 147 patients with LAMN were included and divided into two groups of patients: 50 patients diagnosed incidentally during unrelated investigation and 97 patients presenting with disease-related symptoms. The groups were comparable in distribution of sex, BMI, ASA class, preoperative assessment, and perioperative course. Patients in the incidental group were overall older and had significantly lower rates of pseudomyxoma peritonei (PMP) (26% vs 51%, p=0.02). At a mean follow up of 32 months, the recurrence rate was significantly lower for the incidental finding group (2% vs 20%, p<0.01) and DFS was longer (mean months; 32 vs 28 months, p<0.01). OS was comparable (mean months; 33 vs 32). In the subgroup of patients with PMP, incidental finding remained a significant predictor of lower recurrence rates (8% vs 38%, p=0.04) and prolonged DFS (mean months; 36 vs 47, p=0.04).
Conclusion: Patients with LAMN who were symptomatic at the time of diagnosis were 10 times more likely to experience recurrence, 2 times more likely to have PMP, and had significantly worse DFS. This significant finding remains true even when stage-matched.
