A 5-year-old boy with a large hereditary multiple exostoses lump grown into thoracic cavity.

Multiple exostosis is associated with the autosomal dominant disorder and hereditary multiple exostoses (HMEs), are rarely growing around the ribs and the formation of a large lump into the thoracic cavity. It's generally agreed that when there are no symptoms present, a HME patient could either avoid any treatment or postpone the operation until adolescence. We present a 5-year-old boy with 4 cm × 3.5 cm HMEs lump invasion into the thoracic cavity, with symptoms of chest distress and right chest pain. This patient received video-assisted thoracoscopic surgery (VATS) and a the lump and 1 cm rib involved was resected. During a 2 years follow-up, the patient remained in good condition without recurrence and complications.