title: Periosteal osteoblastoma of the distal femur.
abstract: Osteoblastomas located on the surface of the cortical bone, so-called periosteal osteoblastomas, are extremely rare. We report on a case of periosteal osteoblastoma arising from the posterior surface of the right distal femur in a 17-year-old man. Roentgenographic, computed tomographic, magnetic resonance imaging, and histologic features of the case are presented. Periosteal osteoblastoma should be radiologically and histologically differentiated from myositis ossificans, avulsive cortical irregularity syndrome, osteoid osteoma, parosteal osteosarcoma, periosteal osteosarcoma, and high-grade surface osteosarcoma. Although periosteal osteoblastoma is rare, this tumor should be included in the differential diagnosis of surface-type bone tumors.
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nakatani
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Akisue
authors.forename: Takashi
authors.initials: T
authors.lastname: Marui
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Hitora
authors.forename: Teruya
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Nagira
authors.forename: Ikuo
authors.initials: I
authors.lastname: Fujita
authors.forename: Keiji
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yoshiya
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000175:diagnosis*; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018215:Osteoblastoma / Q000175:diagnosis*; D010521:Periosteum / Q000473:pathology; D014057:Tomography, X-Ray Computed