Hidden Malignancies: A 10-Year Review of Appendiceal Neoplasm Rates in Hawke's Bay Compared to International Trends

Appendiceal neoplasms are rare but clinically significant findings in appendicectomy specimens. An international meta-analysis reports a malignancy rate of 1.98%. This study aimed to determine the local incidence of appendiceal neoplasms at Hawke's Bay Hospital, New Zealand, over a 10-year period and compare it with international data.

A retrospective review was conducted of all appendicectomies performed at Hawke's Bay Hospital between January 2014 and December 2023. Demographic and histopathological data were extracted from electronic medical records. Neoplasms were classified as carcinoid tumours, mucinous neoplasms, or adenocarcinomas. Patients were categorised by ethnicity and rurality.

Of 2333 appendicectomy specimens with complete histology, 67 (2.87%) were neoplastic. These included 27 neuroendocrine tumours (40.3%), 25 mucinous neoplasms (37.3%), and 15 adenocarcinomas (22.4%). Patients of New Zealand European ethnicity accounted for 71.6% of cases, while Māori represented 22.4%. The majority of neoplastic cases (91%) were from urban areas. Nearly half of patients with appendiceal neoplasm have their surgery at < 50 years of age (n = 33) and would therefore fall outside of the scope of routine post-appendicitis colonoscopic evaluation at our institution.

The local incidence of appendiceal neoplasms (2.87%) was higher than the internationally reported rate of 1.98%. Neuroendocrine tumours were the most common subtype. The predominance of Urban and New Zealand European cases may reflect access to surgical services or demographic distribution. These findings highlight the importance of routine histopathological evaluation of appendicectomy specimens to ensure timely diagnosis and management of neoplasms.