Asymptomatic costal exostosis with thickening in the pericardium: a case report

BACKGROUND: Costal exostosis is a benign condition that sometimes requires emergent surgery because of associated hemothorax; in addition, there have been cases with malignant transformation to chondrosarcoma. Here, we describe an asymptomatic patient who underwent thoracoscopic resection for primary costal exostosis. CASE PRESENTATION: A 16-year-old male was found to have a bow-shaped shadow on a chest X-ray. Chest computed tomography revealed a rod-like mass with a soft tissue shadow adjacent to the left fifth rib. A thoracoscopic partial resection of the left fifth rib was performed. Intraoperative findings included thickening of the pericardium near the tip of the growth and erosion of the visceral pleura of the left lung. The resected specimen was diagnosed as a primary costal exostosis based on histopathological findings. CONCLUSIONS: We review the published literature on costal exostosis and discuss the surgical indications of asymptomatic cases.