Gallbladder Agenesis and False-Negative Functional Imaging: A Case Report.

Gallbladder agenesis is a rare congenital anomaly that may present with biliary colic-like symptoms and is frequently misdiagnosed, as non-visualisation of the gallbladder on ultrasound is often attributed to contraction or chronic disease, and functional imaging may further obscure the diagnosis if anatomical absence is not first excluded. We report a case of a 46-year-old female with a 10-year history of recurrent right upper quadrant pain consistent with biliary colic, in whom multiple ultrasounds failed to visualise the gallbladder and showed no gallstones, with persistently normal liver function tests. Magnetic resonance cholangiopancreatography (MRCP) demonstrated complete gallbladder agenesis with an otherwise normal biliary tree; however, subsequent endoscopic ultrasound and hepatobiliary scintigraphy suggested the presence of a functioning gallbladder with a high ejection fraction. Based on persistent symptoms and apparently reassuring functional imaging, laparoscopic cholecystectomy was undertaken, during which a complete absence of the gallbladder and cystic duct was confirmed intraoperatively. This case demonstrates that functional nuclear medicine imaging may actively contradict definitive anatomical imaging, falsely implying a normally functioning gallbladder in patients with gallbladder agenesis due to unimpeded bile flow into the small intestine. MRCP was the only modality that correctly identified the diagnosis, and early consideration of gallbladder agenesis with prioritisation of MRCP in patients with biliary-type pain and repeated gallbladder non-visualisation on ultrasound may prevent unnecessary surgery.