Challenging Diagnosis of Intrapancreatic Accessory Spleen in the Tail of the Pancreas: A Case Report

Objective: Rare diseaseBackground: Intrapancreatic accessory spleen, or splenunculus, is a congenital condition that occurs in up to 2% of the pop-ulation, with the tail of the pancreas being the second most common site. Imaging alone may not confirm the diagnosis as this can mimic a hypervascular tumor on contrast-enhanced computed tomography (CT) and mag-netic resonance imaging (MRI). This report presents a challenging case of intrapancreatic accessory spleen in the tail of the pancreas in a 64-year-old man.Case Report: A 64-year-old man was admitted for a space-occupying lesion in the tail of the pancreas. CT, MRI, and posi-tron emission tomography-CT could not confirm the diagnosis. Endoscopic ultrasound-guided fine-needle as-piration biopsy was not performed given the potential for greater risk. The mass in the patient's pancreatic tail was considered benign or low-grade malignant. The patient then underwent a robotic pancreatectomy to re-move the tumor in the tail of the pancreas. We performed intraoperative ultrasound scanning and detected a hypoechoic nodule in the body of the pancreas. This nodule had a clear boundary, and color Doppler flow im-aging showed that there was no definite blood flow signal in it. The pathology diagnosis after surgery was in-trapancreatic accessory spleen. The patient recovered without other complications and was discharged 5 days later.Conclusions: This report highlights the importance of considering the diagnosis of intrapancreatic accessory spleen in hy-pervascular lesions seen on imaging alone and of confirming the diagnosis with definitive cytopathology or histopathology.