title: Periosteal osteoblastoma: report of a case with a rare histopathologic presentation and review of the literature.
abstract: Osteoblastoma is an uncommon benign bone tumor most commonly located in the vertebral column or metaphysis of a long bone. Periosteal location is rare. We report a periosteal-based osteoblastoma, arising from the proximal tibia, in a 20-year-old woman who presented with knee swelling and pain of 2-year duration. Imaging studies showed a metaphyseal surface-based lesion with patchy radiodensities. The cortico-medullary junction was intact. The lesion was totally excised. Histopathologic evaluation disclosed immature bone and osteoid deposition in a vascularized stroma, associated with numerous osteoblasts and osteoclasts rimming the bony trabeculae. Plate-like arrangements of cartilage in the margin of the neoplastic tissue were also identified. At 16 months postoperatively, the patient was well without recurrence. Although extremely unusual, the presence of cartilage does not necessarily exclude the diagnosis of osteoblastoma.
authors.affiliation: Department of Orthopedic Surgery, Imam Hospital, Tehran University of Medical Sciences, Tehran, Iran. smjmort@yahoo.com
authors.forename: S M Javad
authors.initials: SM
authors.lastname: Mortazavi
authors.forename: Doris
authors.initials: D
authors.lastname: Wenger
authors.forename: Saeed
authors.initials: S
authors.lastname: Asadollahi
authors.forename: Shams
authors.initials: S
authors.lastname: Shariat Torbaghan
authors.forename: K Krishnan
authors.initials: KK
authors.lastname: Unni
authors.forename: Sadegh
authors.initials: S
authors.lastname: Saberi
mesh_terms: D000328:Adult; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D018215:Osteoblastoma / Q000175:diagnosis* / Q000473:pathology; D010521:Periosteum / Q000473:pathology*; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed