Imaging of spontaneous biliary perforation in neonates: focus on ultrasound findings with a review of the literature.

Spontaneous biliary perforation in neonates is a rare but potentially life-threatening condition with nonspecific clinical presentation. Early diagnosis is challenging due to nonspecific clinical signs, yet it is critical for appropriate management. Our objective is to present two etiologically distinct cases of neonatal spontaneous biliary perforation and to review the literature, with a focus on imaging findings, particularly the role of ultrasound (US) in diagnosis. Abdominal US was the initial imaging modality. Indirect ultrasound signs, such as fluid collections near the gallbladder extending towards the duodenum, the porta hepatis, and further into the abdomen, gallbladder wall thickening, and bile duct abnormalities, helped raise suspicion of spontaneous biliary perforation. US findings can be nonspecific, and the direct sign - the so-called 'hole sign' - is rarely observed. The final diagnosis was confirmed using magnetic resonance cholangiopancreatography, hepatobiliary iminodiacetic acid scanning, and intraoperative cholangiography. A literature review was conducted focusing on the role of imaging in 23 neonatal cases of spontaneous biliary perforation reported since 1995. Ultrasound was the initial diagnostic tool in 19 cases. In eight cases (42%), US findings raised suspicion of spontaneous biliary perforation, including two cases with direct and six with indirect signs. Hepatobiliary iminodiacetic acid scanning and magnetic resonance cholangiopancreatography served as confirmatory methods. In 65.2% of cases, the diagnosis was ultimately confirmed surgically. Ultrasound plays an important role in the early diagnosis of spontaneous biliary perforation in neonates, mostly through recognition of indirect signs, highlighting the importance of familiarity with this entity.