Abstract

Background: Appendiceal neuroendocrine neoplasms (ANENs) are rare tumors often discovered incidentally during procedures like appendectomies. Routine histological evaluation of appendectomy specimens is crucial, as it may reveal unexpected findings such as ANENs.
Objective: To present a case of a well-differentiated ANEN identified incidentally following a subhepatic appendectomy.
Case Presentation: A 38-year-old female presented with acute right upper quadrant abdominal pain. A contrast-enhanced computed tomography scan of the abdomen and pelvis revealed a slightly dilated appendix (7 mm in diameter) located in the subhepatic area. The scan showed minimal fluid collection around the appendix tip, mild fat stranding, and partial aeration, indicating catarrhal appendicitis. The atypical subhepatic location of the appendix with a partially aerated tip posed a diagnostic challenge. Two weeks after the appendectomy, histopathological analysis of the excised specimen revealed a well-differentiated ANEN.
Conclusion: This case of an ANEN discovered after a subhepatic appendectomy underscores the importance of routine histopathological examination of the excised appendix to identify unexpected findings.

Key words: appendiceal neuroendocrine neoplasm, subhepatic appendicitis, well-differentiated tumor, histopathological examination