Background and Aims 

Ectopic pancreas is an uncommon subepithelial lesion typically located in the duodenum or gastric antrum. Although EUS-guided tissue acquisition can assist in differentiating these lesions from gastrointestinal stromal tumors or neuroendocrine neoplasms, biopsy of ectopic pancreatic tissue may, in rare instances, precipitate acute inflammation. We report a unique case of acute ectopic pancreatitis triggered by EUS-guided fine needle biopsy (EUS-FNB) of a duodenal lesion, underscoring the importance of procedural awareness and post-biopsy monitoring. 

Case Description 

A 55-year-old man with a history of coronary artery disease and GERD presented with right upper quadrant pain. Cross-sectional imaging revealed a 1.9 cm ovoid lesion in the distal duodenum, initially suspected to be a gastrointestinal stromal tumor. EUS demonstrated a 19 mm well-defined hypoechoic submucosal lesion arising from the muscularis propria, containing small anechoic foci suggestive of ductal elements. Under Doppler guidance, four passes were made using a 22-gauge SharkCore FNB needle. No immediate complication occurred. Within 6 hours post-procedure, the patient developed worsening abdominal pain and low-grade fever. Laboratory testing showed mild lipase elevation (59 U/L). CT abdomen revealed duodenal wall thickening and perilesional fat stranding, consistent with localized pancreatitis. The patient was managed conservatively with bowel rest, intravenous fluids, and analgesia, with full recovery within 72 hours. Histopathology confirmed benign pancreatic acinar and ductal tissue, diagnostic of ectopic pancreas. 

Results 

The clinical, imaging, and histologic correlation established the diagnosis of acute ectopic pancreatitis secondary to EUS-FNB. At two-month follow-up, the patient remained asymptomatic without recurrence. 

Conclusions 

Ectopic pancreatitis following EUS-guided biopsy is exceptionally rare, with only isolated cases reported in the literature. This case illustrates how needle-induced ductal injury within ectopic pancreatic tissue can provoke acute inflammation. Awareness of EUS features characteristic of ectopic pancreas should guide procedural decision-making and may prevent unnecessary tissue acquisition.