Well-Differentiated Neuroendocrine Tumor of the Appendix Presenting as Acute Phlegmonous Appendicitis: A Case Report

Case PresentationA 26-year-old male patient was admitted as an emergency case due to acute abdominal pain with a 2-day history of symptoms.The pain started in the epigastrium and localized to the right iliac fossa.The patient was febrile (38C), with nausea, repeated vomiting, and loss of appetite.Past medical history was negative for hepatic, renal, or malignant diseases, and no drug allergies were reported.The patient had marked tenderness in the right lower quadrant on superficial and deep palpation.Laboratory results were as follows: white blood cell count =810 9 /L, neutrophil-to-lymphocyte ratio (NLR) =2.55, C-reactive protein (CRP) = 56.5 mg/L, procalcitonin = 0.08 ng/ ABSTRACTA 26-year-old man underwent appendectomy for acute phlegmonous appendicitis, and postoperative histopathology revealed a well-differentiated appendiceal neuroendocrine tumor (NET) (G1, 1.3 cm, Ki-67 <1%), confined to the subserosa without mesoappendiceal invasion or lymphovascular/ perineural involvement.Surgical margins were clear, and the patient recovered uneventfully.According to guidelines, right hemicolectomy is selectively considered for 1-2 cm tumors with high-risk features.As none were present, appendectomy was deemed sufficient following a multidisciplinary team review.This case highlights the importance of thorough histopathological assessment and individualized management of incidentally detected appendiceal NETs within the 1-2 cm gray-zone category.