title: Pediatric extraskeletal osteosarcoma.
abstract: Extraskeletal osteosarcoma (ESOS) is a rare malignant tumor composed of mesenchymal cells comprising approximately 1% of soft-tissue sarcomas and 4% of all osteosarcomas. Primary osseous osteosarcomas more commonly develop in children and adolescents, but there are very few reports of ESOS occurring in those younger than 40 years. These variants of high-grade osteosarcoma are often characterized histopathologically by the production of an osteoid matrix and bone from malignant osteoblasts that by definition are present in the soft tissue outside the normal skeletal anatomy. We present a 13-year-old girl with a gradually enlarging, painless left thigh mass.
authors.affiliation: Clinical Radiology of Oklahoma, PO Box 2814, Edmond, OK 73083, USA.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Beall
authors.forename: Justin
authors.initials: J
authors.lastname: Ly
authors.forename: Jayson P
authors.initials: JP
authors.lastname: Bell
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Parker
authors.forename: Christopher M
authors.initials: CM
authors.lastname: John
authors.forename: Julie C
authors.initials: JC
authors.lastname: Babb
authors.forename: Annette M
authors.initials: AM
authors.lastname: Stapp
mesh_terms: D000293:Adolescent; D001706:Biopsy; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D012516:Osteosarcoma / Q000175:diagnosis*; D011859:Radiography; D035583:Rare Diseases; D012983:Soft Tissue Neoplasms / Q000175:diagnosis*; D013848:Thigh / Q000000981:diagnostic imaging / Q000473:pathology
chemical_list: D003287:Contrast Media