Characteristics and Management of Children with Appendiceal Neuroendocrine Neoplasms: A Single-Center Study

Background/objectives: Appendiceal neuroendocrine neoplasms (ANENs) are usually found incidentally during histology examination after appendectomy for appendicitis. Due to their rarity in pediatric populations, there is no consensus on treatment or follow-up. The analysis of patients with ANENs of our and other studies will increase the understanding of this tumor. Methods: Pediatric patients with ANENs were uniformly managed at our center between 1998 and 2023. Patients' presenting symptoms, surgery, tumor histology, post-surgical work-up, follow-up and outcome were analyzed. Results: Our report describes 17 patients with a diagnosis of ANEN after appendectomy. The median age was 14 years (range of 4-17 years). Tumors were located at the tip of the appendix in 58.8% of cases and only one had a diameter >1 cm. All were well-differentiated tumors with free resection margins. The submucosa was invaded in five cases, muscularis propria in eight and subserosa in four. Post-appendectomy work-up included tumor marker measurement, abdominal ultrasound and computed tomography or magnetic resonance imaging, chest X-ray and octreotide scintigraphy. No residual tumors or metastases were detected. Additional surgery was not necessary. Follow-up was carried out for a median duration of 6 years (range of 1-10 years). Only one patient was lost to follow-up and all other patients are alive without tumor recurrence. Conclusions: The tumor characteristics of our patients confirmed data from the literature. With the lack of a sufficient number of large prospective trials, it is important to add more information to confirm the benign nature and excellent outcome of this tumor, even without additional surgery. Consensus guidelines are needed for ANENs in pediatric populations.