BACKGROUND Bizarre parosteal osteochondromatous proliferation (BPOP), first described by Nora et al. in 1983 and therefore termed "Nora's lesion", is a rare lesion that occurs in the short bones of the hands and feet and eventually presents as a parosteal mass. Reports of BPOP in the long bones are very rare. A benign disease, BPOP does not become malignant, although a high rate of recurrence f...

165 Received February 27, 2014; revised and accepted May 28, 2014. Published online June 26, 2014; doi: 10.1620/tjem.233.165. Correspondence: Yasuhiro Yamamoto, Department of Orthopaedic Surgery, School of Medicine, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan. e-mail: [email protected] Cortical Bone Remodeling in Parosteal Osteosarcoma Mim...

Primary tumors of the calvarium are infrequent, and with the exception of osteoma, lesions confined to the surface of the skull are very rare. The differential diagnosis includes benign and malignant matrix forming tumors, other mesenchymal tumors, and reactive lesions. Fibro-osseous lesions are characteristically centered within bone and surface fibro-osseous lesions always prompt consideratio...

High-grade surface osteosarcoma is the rarest of the three types of surface osteosarcoma. Four cases with high-grade surface osteosarcoma arising from the distal femur and tibia are reported in this study. One patient was previously diagnosed with Turner's syndrome. Radiologically, three cases presented characteristic appearances suggesting high-grade bone-forming sarcoma arising from the bone ...

Osteosarcoma (OS) is a primary malignant bone tumour that usually occurs in children and adolescents. OS highly aggressive type with propensity for local invasion systemic early metastasis to the lungs or other bones. According World Health Organization, there are different subtypes of OS, including conventional (osteoblastic, chondroblastic, fibroblastic), telangiectatic low-grade small-cell p...

Primary osteosarcomas of the skull and skull base are rare and comprise < 2% of all skull tumors. In head and neck osteosarcomas, the chondroblastic subtype occurs most frequently, which has an exceedingly poor outcome, but its image characteristic remains unknown. Herein, we report a case in the right occipital bone of the skull base and the unique characteristics of image. Pathologic examinat...