A Rare Paediatric Case of Double Appendix Anomaly with Appendiceal Neuroendocrine Neoplasm

This case report presents a rare congenital anomaly: the presence of a double appendix, a condition observed in approximately 1 in 25,000 appendectomy cases. The discovery of a neuroendocrine tumour in one of the appendices further underscores the exceptional nature of this case. Present case is of an eight-year-old boy who was admitted with acute abdominal pain, during which emergency surgery revealed a double appendix. While one appendix appeared normal, the other exhibited a yellow nodular lesion suggestive of malignancy. Histopathological evaluation confirmed a Grade I well-differentiated neuroendocrine tumour measuring 1.2 cm. The tumour had invaded the serosa and the proximal surgical margin but showed no lymphovascular invasion. Immunohistochemical analysis demonstrated strong positivity for chromogranin and negativity for synaptophysin, with a low Ki67 index of 3%, corroborating the diagnosis. Following National Comprehensive Cancer Network (NCCN) guidelines, the patient underwent a right hemicolectomy to ensure complete tumour removal and minimise the risk of recurrence. Subsequent histological examination showed no residual tumour or lymph node metastases. The patient recovered well, with no recurrence noted during follow-up. This case highlights the need for careful intraoperative exploration and thorough pathological assessment, particularly when rare anatomical anomalies are encountered. Documenting such unique findings enriches medical knowledge, raises clinical awareness and underscores the value of evidence-based surgical management in achieving optimal outcomes.