CASE REPORT Isolated costal cartilage fracture: an unusual cause of an anterior chest mass in a toddler Robert C. Orth & Tal Laor Received: 30 January 2009 / Revised: 4 March 2009 / Accepted: 2 April 2009 / Published online: 5 May 2009 # Springer-Verlag 2009 Abstract A 17-month-old boy presented with a palpable anterior chest wall mass and was evaluated by chest radiography, sonography, and MRI. No history of trauma was provided initially. Sonography and MRI showed a costal cartilage fracture with overlying hematoma. Identifi- cation of a fracture isolated to the costal cartilage is rare and this is a unique case among children. In the appropriate clinical setting, costal cartilage fractures can be confirmed by sonography alone, and follow-up assessment can be based on clinical evaluation without the need for additional cross-sectional imaging. Keywords Rib fracture . Sonography . Costal cartilage . Child Introduction Costal cartilage fractures are not seen on chest radiographs unless heavily calcified, a process that begins in adulthood [1]. Cartilaginous injuries, however, can be assessed with cross-sectional imaging including sonography, CT, and MRI. Although sonography has been used in several studies in adults for the evaluation of rib pathology, a review of the literature identified only two case studies that specifically address the use of sonography for the diagnosis of traumatic rib injuries in children [2–4]. These include a recent case report by Kelloff et al. [5], which describes the use of sonography for the diagnosis of an acute osseous rib fracture in a 9-week-old boy. A second case report by Smeets et al. [6] describes the sonographic detection of a costochondral dislocation. In both cases, the rib injuries were not identified on chest radiography. This report presents the unique case of a 17-month-old boy who presented with a palpable mass in the mid-anterior chest caused by a fracture isolated to the costal cartilage and seen on both sonography and MRI. Case report An otherwise healthy 17-month-old boy presented to his primary care physician after his parents noticed a tender, palpable mass along the medial aspect of his right anterior chest. No specific trauma history was provided. Bleeding, bruising, or signs of infection were not seen on physical examination. Initial frontal and lateral chest radiographs were normal. Focused sonography showed a relatively well-defined 2-cm solid mass in the subcutaneous tissues corresponding to the palpable abnormality (Fig. 1), with minimal internal Doppler color flow. The child was referred for MRI, which showed a focal, heterogeneous T2-signal intensity mass with peripheral contrast enhancement adja- cent to a non-displaced vertical cartilage fracture of a mid- thoracic rib (Fig. 2). On retrospective review of the sonographic clip se- quence, a fracture isolated to the costal cartilage was identified (Fig. 3). Clinical and sonographic follow-up showed a decrease in mass size, consistent with a resolving hematoma. Calcification was noted adjacent to the healing cartilaginous fracture on follow-up sonography (Fig. 4). A possible fall onto a coffee table was eventually recalled by the child’ s grandfather. Thorough clinical evaluation raised no suspicion of child abuse. Pediatr Radiol (2009) 39:985–987 DOI 10.1007/s00247-009-1276-8 R. C. Orth : T. Laor (*) Department of Radiology, Cincinnati Children’ s Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039, USA e-mail: tal.laor@cchmc.org