BackgroundGallbladder agenesis is a rare congenital malformation. More than 50% of cases are isolated and asymptomatic. These asymptomatic patients are principally healthy and need no interventions. However, some patients develop symptoms, presenting with clinical signs and complaints similar to those of biliary tract disease. Symptoms commonly occur in the fourth or fifth decade of life of the patient. At the present time, gallbladder agenesis is diagnosed using a combination of imaging modalities, without surgical intervention, to avert serious complications following surgery.Case presentationWe describe a 13-year-old Japanese girl with a history of recurrent hepatic impairment, which had not been thoroughly investigated. She was referred to our hospital following 2 days of fever, fatigue, and abnormal blood tests suggested impaired liver function. Data from chest X-ray findings combined with a positive loop-mediated isothermal amplification assay result indicated Mycoplasma pneumoniae pneumonia, which was treated with oral azithromycin. To investigate potential hepatic impairment, we performed several imaging studies, namely, abdominal ultrasonography, magnetic resonance cholangiopancreatography, and contrast enhanced computed tomography. These imaging studies revealed a normal liver; however, the gallbladder was not in the usual nor any aberrant position in imaging investigations of the patient. Based on these results, we diagnosed gallbladder agenesis; however, the etiology of her hepatic impairment has not been elucidated.ConclusionWe present a case of gallbladder agenesis with hepatic impairment, where the diagnosis was made without surgical intervention. Clinicians should perform a detailed investigation when they encounter repeated hepatic impairment.