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

BACKGROUND Intrapancreatic accessory spleen, or splenunculus, is a congenital condition that occurs in up to 2% of the population, 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 magnetic 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 positron emission tomography-CT could not confirm the diagnosis. Endoscopic ultrasound-guided fine-needle aspiration 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 remove 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 imaging showed that there was no definite blood flow signal in it. The pathology diagnosis after surgery was intrapancreatic 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 hypervascular lesions seen on imaging alone and of confirming the diagnosis with definitive cytopathology or histopathology.