Pancreatic Fistula Presenting as Gastric Outlet Obstruction Concerning for Gastric Malignancy: Piecing the Puzzle

Abstract

Background: Gastric outlet obstruction (GOO) is a clinical syndrome comprising epigastric pain and post-prandial vomiting, often due to mechanical obstruction. Compression by intramural pancreatic pseudocysts (PP) resulting in GOO is a well-defined phenomenon. We present the first reported case of GOO secondary to pancreatic fistula leading to an intramural fluid collection of the pylorus. Case: 54 year-old man with recent cholecystectomy presented with non-bilious emesis of 4 days. Patient endorsed outside hospital admission for similar complaints 4 months ago, but spontaneous symptom resolution. He had hypoactive bowel sounds but otherwise non-tender, non-distended abdomen. Rou[ tine lab work was unremarkable. Computed tomography (CT) without contrast described pyloric heterogeneity and gastric distension, and a possibility of gastric malignancy causing GOO. EGD revealed ballooning around the pyloric opening, giving appearance of circumferential pyloric channel tumor. The scope could not be advanced further. Endoscopic ultrasound (EUS) demonstrated a hypoechoic pyloric lesion confined to the deep mucosa. FNA aspirated dark fluid. Fluid analysis: amylase (>75,000 U/L). Enlarged Peri-gastric lymph node FNA was negative for malignancy. Repeat CT with contrast disclosed a 2.4x4.5x5.7cm fluid collection around the pylorus with communication to the pancreatic duct (PD). Fluid collection was drained endoscopically with subsequent placement of PD stent. Patient later disclosed having a remote episode of pancreatitis and prior surgical pseudo cyst drainage, which confirmed our clinical suspicion of pancreatic fistula. Discussion: Most PPs resolve spontaneously and uneventfully. Rarely, PP may have communication with PD, in which case may arise, a rare complication of fistula formation to other viscera. Pathogenesis of PP is believed to be due to disruption of the main PD or peripheral ductules causing leakage and activation of pancreatic enzymes, which further explains the formation of the fistula. Symptomatic fistulae present as pain, fever, septicemia, and compression of neighboring structures. Endoscopic drainage via cystgastrostomy or cystoduodenostomy is the preferred approach followed by placement of PD stent to allow further drainage and fistula healing. Performed independently, both drainages are effective, safe and well-coded and the expertise on these procedures is widespread. Surgical drainage is reserved for recurrence or for endoscopic failures.Figure 1Figure 2Figure 3