Management and prognosis of low-grade appendiceal mucinous neoplasms: A clinicopathologic analysis of 50 cases

Background Low-grade appendiceal mucinous neoplasms (LAMN) are poorly understood lesions characterized by their potential to spread to the peritoneal cavity as pseudomyxoma peritonei (PMP). The purpose of this study was to investigate the clinical and pathologic features and management of these tumors. Methods This was a retrospective study of consecutive patients with LAMN who underwent surgery by a surgical team at the First Affiliated Hospital of China Medical University between 2005 and 2016. Subgroup analyses were performed for patients with PMP. Result The study included 50 LAMN patients, 13 of them with PMP. There were no significant differences in age (p = 0.293) or gender (p = 0.196) at diagnosis between the two groups. There was no significant difference in their presentation (p = 0.700). Although 5 patients with PMP had perforation of the appendiceal mucinous, acute peritonitis was uncommon. Microscopic examination detected that PMP without any obvious perforation in tumors shown mucin and/or mucinous epithelium herniating into the appendiceal wall, or as islands within these tissues. The patients underwent appendectomy, caecectomy and right hemicolectomy according to the intraoperative situation. The median follow-up period was 53 months (range 11–146 months). None of the patients developed clinical progression in either group during the follow-up period. Conclusion The age of LAMN at presentation was almost 60 years (56.7) and there was no clear gender predilection. When LAMN was treated surgically with resection of the primary site in early stage disease or with pushing invasion, there was an excellent prognosis and expanded surgical procedures were unnecessary.