Appendiceal Neuroendocrine Tumor Presenting as Acute Appendicitis: A Case Report.

Appendiceal neuroendocrine tumors (NETs), historically referred to as carcinoid tumors, are the most common primary neoplasms of the appendix and are frequently diagnosed incidentally following surgery for suspected acute appendicitis. Preoperative diagnosis is uncommon because their clinical presentation often mimics inflammatory appendiceal disease. We report the case of a 30-year-old male who presented with a 48-hour history of right lower quadrant abdominal pain, nausea, vomiting, and fever, consistent with acute appendicitis. Due to clinical suspicion of complicated appendicitis, the patient underwent emergency exploratory laparotomy. Intraoperative exploration revealed a firm heterogeneous mass measuring approximately 6 cm involving the appendix, cecum, and ileocecal valve, prompting en bloc surgical resection with protective ileostomy. Gross examination demonstrated an exophytic appendiceal mass with irregular contours. Histopathological analysis confirmed a well-differentiated appendiceal neuroendocrine tumor with negative surgical margins. Postoperative thoracoabdominopelvic computed tomography showed no evidence of lymph node involvement, local recurrence, or distant metastases. The patient experienced an uneventful postoperative recovery and was referred for oncologic follow-up. This case highlights the importance of considering appendiceal neoplasms in patients presenting with acute appendicitis and underscores the role of intraoperative assessment, histopathological evaluation, and appropriate surgical management in achieving favorable outcomes.