Data regarding the clinical impact of subspecialist pathology review of appendiceal neoplasms are limited. To determine whether pathology review by gastrointestinal pathologists at a tertiary-care referral center resulted in significant changes in the diagnosis and clinical management of appendiceal neoplastic lesions. We conducted a retrospective review of all patients with an initial diagnosis of appendiceal neoplasm referred to a tertiary-care referral center in Ontario, Canada, from 2010-2016. The discordance rate between original and review pathology reports, the nature of discordances, and the impact of any discordance on patient management were recorded. A total of 145 patients with appendiceal lesions were identified (low-grade mucinous appendiceal neoplasm n = 79, invasive mucinous adenocarcinoma n = 12, "colorectal type" adenocarcinoma n = 12, goblet cell carcinoid and adenocarcinomas ex goblet cell carcinoid n = 24, and other lesions/neoplasms n = 20). One or more changes in diagnoses were found in 36 of 145 cases (24.8%), with changes within the same category of interpretation (n = 10), stage (n = 7), grade (n = 6), and categoric interpretation (n = 5) being the most common. In 10 of 36 patients (28%), the diagnostic change led to a significant change in management, including recommendation for additional surveillance, systemic chemotherapy, additional surgery, or discontinuation of surveillance. Subspecialist pathology review of appendiceal neoplastic lesions led to a change in diagnosis in 36 of 145 cases (24.8%), of which nearly 30% (10 of 36 cases) led to a change in clinical management. The overall rate of clinically significant discordances was 7% (10 of 145). Our findings suggest that subspecialist pathology review of appendiceal neoplasms referred to specialized centers is justified.