Exostosis occurs in the ribs either sporadically or as a manifestation of a genetic disorder known as hereditary multiple
exostoses. Costal exostosis may cause chest pain and, on rare occasions, result in hemothorax. We report a case of hemothorax
owing to costal exostosis in a 4-year-old boy.
Key words Exostosis - Rib - Hemothorax