Intrapancreatic Accessory Spleen: Utilization of Fine Needle Aspiration for Diagnosis of a Potential Mimic of a Pancreatic Neoplasm

Accessory spleen (AS) is not a rare occurrence, and with the second most common site being the tail of the pancreas, intrapancreatic AS (IPAS) can easily mimic a pancreatic neoplasm. Together with radiologic imaging findings, endoscopic ultrasound-guided fine needle aspiration (FNA) can be used to assist in the diagnosis, preventing potentially unnecessary surgical procedures. The most common cytologic findings that have been described in the literature include a heterogenous population of small lymphocytes along with traversing small vessels. Immunohistochemical staining for CD8 has also been documented as a useful tool to support the diagnosis as it specifically highlights the endothelial cells of the splenic sinus. Here, we report two additional cases of IPAS diagnosed by FNA and discuss the potential pitfalls in diagnosis of this entity.