Oncologic Risk of Missed Appendiceal Tumors in Acute Appendicitis

Area of Science:

• Gastroenterology
• Oncology
• Surgical Pathology

Background:

• Antibiotic-only management (AOM) for acute appendicitis is gaining traction.
• This raises concerns about potentially missing appendiceal neoplasms during AOM.

Purpose of the Study:

• To determine the prevalence and histological types of incidental appendiceal tumors found after appendectomy.
• To identify predictors of these tumors, particularly aggressive ones.

Main Methods:

• Retrospective cohort study of adult patients undergoing appendectomy for acute appendicitis.
• Analysis of preoperative clinical, laboratory, and imaging data to identify tumor predictors.
• Evaluation of established AOM eligibility criteria against identified tumor cases.

Main Results:

• 1.6% of appendectomies revealed malignant or premalignant lesions; 0.3% had benign lesions.
• Neuroendocrine tumors (NETs) were most common (1.0%), typically small, low-grade, and without recurrence.
• Aggressive tumors were associated with older age, longer symptom duration, larger appendiceal diameter, and suspected complicated appendicitis on imaging.
• Established AOM selection criteria excluded patients with aggressive tumors but included many with small, low-grade NETs.

Conclusions:

• Incidental appendiceal tumors are uncommon, with aggressive malignancies being rare.
• Small, low-grade NETs are the most frequent finding.
• Preoperative selection criteria can effectively identify patients suitable for AOM, ensuring oncologic safety.