Hereditary multiple exostosis (HME) is a rare skeletal genetic disorder with multiple and disseminated osteochondromas. Costal localization is found in 40% of cases. Surgery for asymptomatic lesions remains controversial, but some lesions can be life-threatening. We report the case of a 10-year-old girl with HME, who developed a sharp costal exostosis compressing the hepatic parenchyma, for which a prophylactic resection was decided. The complete excision of the lesion was performed through extraperitoneal approach under video-assisted laparoscopy control, without short-and mid-term complication. To our knowledge, our case is the first in the literature where exostosis threatens the hepatic parenchyma.