Intrapancreatic accessory spleen mimicking a pancreatic neuroendocrine tumour - An important but almost forgotten differential diagnosis.

Abstract: Intrapancreatic accessory spleen (IPAS) is a rare condition resulting from the failure of embryological splenic buds to fuse. Found in approximately 1.1% to 3.4% of the population, IPAS can present significant diagnostic challenges, often mimicking pancreatic tumours such as pancreatic neuroendocrine tumours. We report two cases of IPAS, each illustrating different diagnostic approaches and outcomes. These cases highlight the importance of considering IPAS in differential diagnoses for hypervascular pancreatic tail lesions. Advanced imaging techniques such as magnetic resonance imaging, computerised tomography, technetium-99m scintigraphy and endoscopic ultrasound-guided fine-needle aspiration are critical in distinguishing IPAS from malignant conditions, potentially preventing unwarranted surgical interventions. Comprehensive diagnostic protocols combining multiple modalities are recommended to enhance diagnostic accuracy and optimise patient outcomes.