The pitfalls of gallbladder agenesis combined with small bowel malrotation

Gallbladder agenesia is a rare congenital anomaly that is frequently overlooked in clinical practice, often misdiagnosed as chronic sclero-fibrous cholecystitis or cholelithiasis. Failure to recognize it intraoperatively can prompt unnecessary and hazardous exploration of the biliary tree and liver, increasing the risk of iatrogenic injuries. This report describes a rare case of gallbladder agenesia coincidentally discovered during surgery, alongside adult midgut malrotation—both diagnosed intraoperatively. The patient presented with symptoms mimicking biliary colic, which, in 23–55% of gallbladder agenesia cases, lead to symptomatic presentation. Preoperative ultrasound commonly misinterprets the absent gallbladder as a shrunken, hypoplastic, or contracted organ due to artifacts from intestinal gas or adjacent structures. In the presented case, symptoms and ultrasound misinterpretation were likely attributable to the malrotated jejunum positioned beneath the liver. Magnetic resonance imaging (MRI), particularly MR cholangiography, is recommended when ultrasound findings are inconclusive or suggest a scleroatrophic gallbladder, though misinterpretation remains possible due to the condition’s rarity and low clinical awareness. Intraoperatively, overzealous dissection poses the greatest risk. Authors advocate aborting the procedure upon suspicion of agenesia, followed by postoperative confirmatory imaging (CT or MRI), rather than extensive exploration. Adult midgut malrotation is also uncommon, with only 10% diagnosed in adulthood. Most cases are asymptomatic or cause vague abdominal symptoms (pain, nausea, bilious vomiting), often mistaken for biliary pathology. The patient exhibited duodenal nonrotation with right jejunal positioning and normal colon (DNJRCR type). In asymptomatic incidental findings, a conservative approach is recommended. In summary, heightened suspicion for gallbladder agenesia is essential in ambiguous ultrasound reports. Preoperative MRI can prevent unnecessary surgery, while intraoperative recognition should prompt procedure termination and postoperative imaging to avoid iatrogenic complications.