Is right hemicolectomy ever necessary for low-grade and high-grade appendiceal mucinous neoplasm (LAMN and HAMN)? A systematic review of the literature.

[BACKGROUND] Low-grade and high-grade appendiceal mucinous neoplasms (LAMN and HAMN) are rare appendiceal tumours. When confined to the appendix, their prognosis is generally favourable. However, there remains a potential risk of progression to pseudomyxoma peritonei (PMP) or distant metastases. Historically, this perceived risk has led to extensive surgical resections for non-disseminated cases, with right hemicolectomy (RHC) still frequently performed. Despite this, standardised guidelines remain limited and largely based on expert consensus rather than high-level evidence. This study aimed to evaluate the necessity of RHC in the management of non-disseminated LAMN and HAMN.

[METHODS] A comprehensive literature search was conducted across PubMed, Cochrane Library, Web of Science and Google Scholar to identify articles reporting cases of non-disseminated LAMN or HAMN treated with RHC and including histopathological assessment of lymph node status. Studies were excluded if they involved patients who did not undergo RHC, presented with PMP, included other tumour types or lacked lymph node data.

[RESULTS] Thirty articles published between 2009 and 2025 were included, comprising 306 LAMN and 31 HAMN cases treated with RHC. Follow-up period ranged from 1 to 146 months for LAMN and 4-171 months for HAMN. Across all studies, no lymph node metastases were identified on histopathological examination.

[CONCLUSIONS] This systematic review represents one of the largest analyses on non-disseminated LAMN and HAMN cases treated with RHC. The consistent absence of nodal involvement suggests that lymphadenectomy provides no oncological benefit, thereby questioning the necessity of completion surgery in these rare tumours.