Diagnosis of intrapancreatic accessory spleen by endoscopic ultrasound-guided fine-needle aspiration mimicking a pancreatic neoplasm: a case report and review of literature.

Accessory spleen (AS) is a benign condition, where ectopic spleen tissue can be found elsewhere in the abdomen and pelvis, with approximately 20% of cases located at or in the tail of the pancreas. When discovered on imaging, it can be mistaken for conditions that do require surgical removal, including neuroendocrine tumor, and so accurate diagnosis of AS can prevent unnecessary surgery. Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is a commonly performed diagnostic modality that can lead to a confirmatory diagnosis of AS. We present a case of AS diagnosed at our institution by EUS-FNA and review the literature for all reported cases of AS that have been confirmed by EUS-FNA.