Background: Cholecystoduodenal fistula is a rare complication of chronic gallstone disease, accounting for the majority of cholecystoenteric fistulas. Its clinical presentation is often nonspecific, making preoperative diagnosis challenging. The occurrence of gallstone emesis is exceptionally uncommon and may provide an important diagnostic clue to the presence of a biliary-enteric fistula.

Case Presentation: A 30-year-old woman presented with a one-year history of recurrent right upper quadrant abdominal pain and a six-month history of recurrent vomiting. One month before presentation, she reported multiple episodes of vomiting hard, stone-like material and brought the expelled stones for evaluation. Physical examination revealed right hypochondrial tenderness and no scleral icterus. Laboratory investigations were unremarkable. Abdominal ultrasonography demonstrated chronic calculous cholecystitis with choledocholithiasis. Magnetic resonance cholangiopancreatography confirmed gallbladder and common bile duct calculi and suggested a biliary-enteric fistula. Contrast-enhanced computed tomography subsequently demonstrated a fistulous communication between the gallbladder and the duodenum, establishing the diagnosis of cholecystoduodenal fistula secondary to chronic cholelithiasis with choledocholithiasis. The patient underwent open cholecystectomy with fistula takedown, primary duodenal repair, choledocholithotomy, and T-tube drainage. Her postoperative recovery was uneventful, and follow-up cholangiography showed normal biliary drainage without residual stones or leakage.

Conclusion: Cholecystoduodenal fistula is an uncommon but significant complication of long-standing gallstone disease. Gallstone vomiting represents an exceptionally rare clinical manifestation that should prompt consideration of a biliary-enteric fistula. Careful clinical assessment combined with advanced imaging modalities such as CT and MRCP facilitates accurate diagnosis and surgical planning. Early recognition and definitive surgical management are essential for preventing complications and achieving favorable outcomes.

KEYWORDS: Cholecystoduodenal Fistula, Cholelithiasis, Choledocholithiasis, Gallstone emesis, Biliary-enteric Fistula, Chronic Calculous Cholecystitis, Open Cholecystectomy, Case Report.