Appendiceal Neuroendocrine Neoplasms: A Comprehensive Review

Area of Science:

• Gastroenterology and Oncology
• Pathology and Radiology

Background:

• Appendiceal neuroendocrine neoplasms (NENs) are the most frequent malignant tumors of the appendix.
• These tumors exhibit diverse morphology, secretory functions, and genomic profiles, often presenting asymptomatically or with vague abdominal pain.

Purpose of the Study:

• To provide a comprehensive overview of appendiceal NENs.
• To detail imaging, histopathological classification, staging, and management guidelines for early and advanced stages.

Main Methods:

• Review of current literature on appendiceal NENs.
• Focus on imaging characteristics, WHO classification, AJCC/UICC and ENETS staging systems.
• Discussion of treatment protocols, including targeted therapies and follow-up.

Main Results:

• Appendiceal NENs are often detected incidentally after appendectomy, though some present with hormonal excess (carcinoid syndrome).
• High-grade tumors can be aggressive with metastasis at presentation.
• The review synthesizes guidelines for reporting, interpretation, and management.

Conclusions:

• Effective management of appendiceal NENs requires a multidisciplinary approach integrating imaging, pathology, and staging.
• Advanced treatments like radiotherapy, chemotherapy, and somatostatin analogs are crucial for advanced disease.
• Further research into location-specific biomarkers and tumor biology is warranted.