Mediastinal extracardiac fetal rhabdomyoma; Case report

A 9-month-old girl with a small suprasternal mass was referred for treatment after fine needle aspiration of the mass elsewhere suggested rhabdomyosarcoma. On admission, magnetic resonance imaging (MRI) identified a 58 × 42 mm oval mass in the anterior mediastinum close to the common carotid artery and aortic arch. Surgical intervention was initially considered to be too risky, but after a trial of chemotherapy failed to reduce the size of the tumor, complete local excision was planned through a vertical median thoracic incision with median sternotomy. Surgery was performed when she was 10 months old. Due to severe adhesions, the left clavicle, first rib and the sternoclavicular joint needed to be partially resected to allow the tumor to be completely excised with safety. Operating time was 3 h; intraoperative blood loss was 123 mL requiring intraoperative transfusion. Histopathology and immunohistochemistry were consistent with an intermediate form of fetal rhabdomyoma. The postoperative course was uneventful and she is currently alive with no evidence of disease 4 years later. Fetal rhabdomyoma is rare and our case presented with a small, asymptomatic, suprasternal mass. While the distinction between rhabdomyoma and rhabdomyosarcoma can be difficult, a multidisciplinary approach enabled surgery to be performed successfully.