title: [Diagnosis of pleural cavity extraskeletal osteosarcoma: a case report and literature review].
abstract: OBJECTIVE
  To describe the manifestations and diagnosis of pleural cavity extraskeletal osteosarcoma (ESO).
  
  
  METHODS
  One case of ESO diagnosed at the Research Institute of Tuberculosis, 309th Hospital of PLA was reported. Six cases reported in the literature were reviewed.
  
  
  RESULTS
  Chest CT of a middle-aged man revealed an enormous heterogeneous neoplasm, about 10.9 cm x 9.2 cm x 17.7 cm in size, in the left pleural cavity. There was abundant calcification in the tumor, with signs of invasion into the diaphragm and the pleura. Pleural effusion of the left thoracic cavity was also seen on the chest CT. Osteosarcoma was confirmed by pathological study after surgical resection of the tumor.
  
  
  CONCLUSIONS
  ESO is a rare malignant soft tissue sarcoma. Pleural cavity ESO is insidious and imaging studies often reveal a huge mass with abundant calcification. The differential diagnosis includes benign and malignant diseases of the thorax.
authors.affiliation: 309th Hospital of PLA, Beijing 100091, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Chang-Bin
authors.initials: CB
authors.lastname: Quan
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Xin-Jing
authors.initials: XJ
authors.lastname: Wang
authors.forename: Jing-Ying
authors.initials: JY
authors.lastname: Song
authors.forename: Shu-Lin
authors.initials: SL
authors.lastname: Jia
authors.forename: Ming-Gui
authors.initials: MG
authors.lastname: Lin
mesh_terms: D006801:Humans; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma; D035422:Pleural Cavity / Q000473:pathology*