Mandibular symphyseal fracture simulated by a foreign body in the chin.

INTRODUCTION: Penetrating foreign bodies occurring after maxillofacial injuries are a diagnostic challenge for the trauma surgeon. Different materials and various sites of penetration in the maxillofacial region are described in the literature. We present the peculiar course of a patient with an endoral retained foreign body after a penetrating facial injury. The diagnostic pitfall in this type of trauma is highlighted owing to the hyperdensity of the foreign body that, at the computed tomographic (CT) axial scan, simulated a vestibular cortical fracture of the mandibular body and deceived both the radiologist and the surgeon. CLINICAL REPORT: We introduce the case of a boy who fell from his bicycle. Computed tomography was performed to detect any bone injuries. The radiologic report stated that a left condylar fracture was presented, associated to a vestibular cortical fracture of the mandibular body. Anamnestic questions revealed that the boy fell from his bicycle in a dug-up street. Clinical examination revealed 2 extraoral open wounds in the subnasal and periorbital areas and an endoral linear wound in the inferior fornix at the mandibular symphyseal region. Consequently, the left condylar fracture was surgically treated, and the mandibular body was explored by the endoral wound revealing an intact cortex: the road metal was removed from the soft tissue of the chin. The initial diagnostic pitfall was clarified: the radiodense foreign bodies penetrated the endoral wound in the soft tissue of the chin during the fall. They simulated a vestibular cortical fracture of the mandibular body at the CT scan deceiving both the radiologist and the surgeon. DISCUSSION: According to the literature, soft tissue foreign bodies can be detected by ultrasonography, plain radiography, CT, and magnetic resonance imaging. Superficially retained foreign bodies are easily detected with ultrasonography if they are not covered by overlying bone or gas. If this easily available technique had been applied initially in this case, the correct diagnosis might have been established at the initial admittance. Deeply located foreign bodies are best visualized by CT. The foreign body in the case introduced was made by radiopaque substance it presented the same radiodensity as the bone.