Nuances in detecting retained foreign bodies: a case report of a glass shard embedded in a child's scalp

Foreign bodies (FBs) are a relatively common reason for admission to the emergency department, with subacutely embedded FBs presenting a diagnostic challenge to physicians. Retained FBs may cause the patient harm and result in litigation when missed. Diagnostic imaging is a powerful tool for localization of FBs and a physician's choice of modality should reflect its anticipated composition. This case report pertains to a 2-year-old boy with a glass shard embedded in his retro auricular scalp who presented with a painful subcutaneous lesion months after an overlying laceration repair at an outside emergency room. The attending neurosurgeon was able to identify a glass shard both on physical examination and axial T2-weighted MRI. Surgical exploration resulted in the removal of a 1-cm square glass shard. Key to the diagnostic potential of imaging is knowledge of a patient's relevant medical history and the composition of the suspected FB. Herein, we describe imaging modalities and their utility in the context of retained glass FBs.