Incidental Diagnosis of a Well-Differentiated Appendiceal Neuroendocrine Tumor Following Appendectomy for Complicated Acute Appendicitis: A Case Report.

Appendiceal neuroendocrine tumors are the most common primary neoplasms of the appendix and are frequently diagnosed incidentally following appendectomy performed for suspected acute appendicitis. We present a case of a 72-year-old woman with a history of hypertension and hypothyroidism who presented with a 24-h history of right lower quadrant abdominal pain associated with nausea and low-grade fever. Non-contrast abdominal computed tomography demonstrated findings consistent with acute appendicitis. An urgent open appendectomy was performed, and intraoperative findings revealed complicated appendicitis with pelvic inflammatory fluid, fibrinopurulent exudates, and distal appendiceal necrosis. Histopathological examination demonstrated a well-differentiated appendiceal neuroendocrine tumor (NET G1, WHO grade 1), with negative surgical margins, absence of lymphovascular invasion, and a mitotic index of less than 1/mm², associated with acute suppurative appendicitis. Given the favorable histopathological findings, no complementary right hemicolectomy was performed, and the patient was managed with clinical follow-up. The postoperative course was uneventful, with oral intake initiated on postoperative day one, diet advancement on day two, and hospital discharge on day three. This case highlights the importance of routine histopathological examination of all appendectomy specimens and reviews current considerations for risk stratification and therapeutic decision-making in patients with appendiceal neuroendocrine tumors.