International Journal of Medical Laboratory

Introduction: Appendiceal mucinous neoplasms (AMNs) are rare tumors. They range from benign cystadenomas to malignant mucinous adenocarcinomas, with potential for peritoneal spread and recurrence, particularly in high-grade or ruptured lesions.
Materials and Methods: This retrospective cross-sectional study aimed to determine the clinicopathologic features in patients with AMNs at Shahid Sadoughi and Shahid Rahnemon Hospitals (2014-2024). Inclusion required both appendiceal and peritoneal pathology specimens. Data were collected from medical records and follow-up interviews, and statistical analysis was performed using the Pearson Chi-square test.
Results: Fifty-seven patients (39 females, 18 males; mean age: 51.26 ± 16.09 years) were included, with the highest incidence in the 50–69 age group (63%). Abdominal pain was the most common symptom (78.9%), followed by a palpable mass (21.1%). Histologically, 68.4% had low-grade appendiceal mucinous neoplasms (LAMN), 21% mucinous adenocarcinoma. Peritoneal metastasis was seen in 47.4%, overall 75% of adenocarcinomas, 46.2% of LAMNs, and none in cystadenomas. Tumor recurrence occurred in six patients (10.5%), 7.7% of LAMN and 25% of mucinous adenocarcinoma of the appendix. No significant associations were found between tumor type or size and recurrence/metastasis. Three deaths (5.3%) were reported; overall survival was 94.7%.
Conclusions: LAMN was the most prevalent AMN subtype, typically with favorable outcomes despite frequent (46.2%) peritoneal involvement. The survival rate in LAMN was 92.3%, with one death reported in a patient with a tumor size of 5-10 cm, while no deaths were reported in mucinous adenocarcinoma of the appendices. Further studies with larger cohorts are needed to clarify prognostic factors and guide management.