Cases of mistaken identity: Avoiding diagnostic pitfalls in pediatric sonography

Ultrasound (US) is the preferred first-line imaging modality for many pediatric abdominopelvic pathologies because of its portability, lack of ionizing radiation, and real-time imaging capability. However, pediatric sonography remains highly operator dependent and vulnerable to diagnostic pitfalls related to scanning technique, patient cooperation, body habitus, and familiarity with pediatric anatomy. This pictorial essay presents a series of illustrative pediatric US cases that were initially misrepresented and, at times, inadequately imaged by sonographers, with the correct diagnoses subsequently established following review, additional imaging, and discussion with pediatric radiologists. Cases include gastroesophageal junction mistaken for pylorus, ruptured appendicitis mistaken for ileocolic intussusception, terminal ileum mistaken for appendix, thickened ileocecal valve mistaken for intussusception, transient small bowel intussusception mistaken for ileocolic intussusception, canal of Nuck hernia mistaken for necrotic lymph node, torsion of epididymal appendix mistaken for epididymitis, and periappendiceal collection mistaken for ovary. Common contributing factors included failure to establish appropriate anatomy, focus on a single imaging plane, incomplete dynamic assessment, and inadequate Doppler evaluation. For each case, key imaging clues and practical strategies to avoid similar pitfalls are reviewed. These cases emphasize the importance of systematic scanning technique, dynamic cine with multiple plane assessment, and close communication between sonographers and pediatric radiologists, particularly in the age of remote imaging. Increased awareness of these "mistaken identity" scenarios may improve diagnostic accuracy, reduce unnecessary intervention, and enhance confidence in pediatric US interpretation. This educational review may be particularly useful for general radiologists, radiology residents, pediatric radiology fellows, and pediatric sonographers.