A case of mesenchymal hamartoma of the chest wall in infancy is report
ed. The presenting symptom was a bulging mass arising from the chest w
all. Computed tomography showed the lesion to be multifocal. A large e
xtrathoracic mass was removed and the defect in the chest wall was rep
aired with a Marlex mesh. Two smaller intrathoracic lesions were obser
ved conservatively and have not enlarged during the past 7 years.