Absent gallbladder discovered during evaluation for biliary pain: case report and literature review.

INTRODUCTION: Gallbladder Agenesis (GA) is a rare congenital anomaly of the biliary tract with reported incidence estimates at 0.03% in general clinical series. Although many patients are asymptomatic, up to half may present with biliary-type symptoms, creating a diagnostic challenge; routine imaging such as ultrasound or Hepatobiliary Iminodiacetic Acid scan (HIDA) may be misleading, and Magnetic Resonance Cholangio-Pancreatography (MRCP) is often required to establish the diagnosis and avoid unnecessary surgery.

CASE PRESENTATION: We report the case of an adult patient presenting with mild biliary-type pain clinically suggestive of gallstone disease. Initial abdominal ultrasonography was inconclusive, failing to clearly visualize the gallbladder and raising suspicion of a contracted or scleroatrophic gallbladder. Further evaluation with Magnetic Resonance Cholangiopancreatography (MRCP) demonstrated complete absence of the gallbladder with compensatory dilation of the common bile duct (CBD), confirming the diagnosis of GA. The patient was managed conservatively with symptomatic treatment and dietary modifications, leading to significant clinical improvement and a significant regression of symptoms.

CONCLUSION: GA is an uncommon but important differential diagnosis in patients presenting with biliary-type pain when the gallbladder is not visualized on ultrasonography. In cases of diagnostic uncertainty, early use of MRCP is crucial to accurately define biliary anatomy and may prevent unnecessary surgical exploration and associated iatrogenic biliary injury. A structured diagnostic approach based on early cross-sectional imaging is essential to reduce diagnostic delay and avoid potentially preventable operative complications.