title: Asymptomatic costal exostosis with thickening in the pericardium: a case report.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. tooru.kameda@med.toho-u.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Kameda
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. takashi.makino@med.toho-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Makino
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. takamitsu.sakai@med.toho-u.ac.jp.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Sakai
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. satoshi.koezuka@med.toho-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Koezuka
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. hajime.ootsuka@med.toho-u.ac.jp.
authors.forename: Hajime
authors.initials: H
authors.lastname: Otsuka
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. hata@med.toho-u.ac.jp.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hata
authors.affiliation: Department of Surgical Pathology, Toho University School of Medicine, Tokyo, Japan. naobumi.tochigi@med.toho-u.ac.jp.
authors.forename: Naobumi
authors.initials: N
authors.lastname: Tochigi
authors.affiliation: Department of Surgical Pathology, Toho University School of Medicine, Tokyo, Japan. kaz@med.toho-u.ac.jp.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Shibuya
authors.affiliation: Division of Chest Surgery, Toho University School of Medicine, Tokyo, Japan. aiyoda@med.toho-u.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Iyoda
mesh_terms: D000293:Adolescent; D058070:Asymptomatic Diseases; D005096:Exostoses / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D006491:Hemothorax / Q000209:etiology; D006801:Humans; D008297:Male; D010496:Pericardium / Q000000981:diagnostic imaging; D010994:Pleura / Q000473:pathology; D012272:Ribs / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed