Malignant osteoblastoma versus osteosarcoma: a case report.

A 33-year-old male developed a slow-growing mass at the anterior aspect of the left tibia for 8 months. The radiologic finding revealed a well-circumscribed osteolytic mass and appeared benign to most radiologists. The lesion was then excised locally. The histology revealed bizarre osteoblasts and osteoclast-like giant cells interspersing in the vascularized stroma and trabeculated osteoids; the periphery of the lesion showed sclerotic mature bones. Malignant osteoblastoma was, therefore, entertained and the patient was treated as such without aggressive surgery and chemotherapy. He has survived for 11 years. However, the diagnosis of malignant osteoblastoma was still a contradiction because of the presence of cartilage foci.

[The essence of osteoid osteomas and osteoblastomas]. / O sushchnosti osteoidnykh osteom i osteoblastom.

178 cases of osteoid osteomas and osteoblastomas collected during 35 years were studied morphologically and roentgenologically (angiography--28 cases). Clear-cut differences between these two lesions were revealed. The differences concerned: 1) the character of the border with the surrounding bone tissue; 2) the morphology of bone structures being chaotic in the osteoblastoma; 3) intensity of proliferation in the osteogenic tissue; 4) differences in the angiographic data. According to the author's opinion osteoblastoma is a blastomogenic process with destructive growth and intensive proliferation. Classical osteoid osteoma does not possess these properties and is the result of dysontogenetic development of the intraosseous vascular system.

[Classification of primary bone tumors]. / Zur Klassifikation primär ossärer Geschwülste.

An expanded classification for bone tumors is presented based on the well known international classification as well as earlier systems. The current status and future trends in this area are discussed.

Fibro-osseous lesions of the jaws.

During the 15 years since the author's 1970 paper on fibro-osseous lesions of the jaws, the subject has continued to interest the clinician and pathologist. Several new entities have been delineated during this period, and new concepts and controversies regarding the diagnosis and management of these lesions have arisen. A classification of fibro-osseous jaw lesions that the author has found to be workable is presented, and criteria for their diagnosis and management based on the authors' experience is discussed.

[Cytological classification of bone tumors]. / Tsitologicheskaia klassifikatsiia opukholei kostei.

The creation of a classification is a first need for the improvement of the cytological diagnosis. The cytologic classification of bone tumours is worked out on the basis of the International Histological Classification. The possibilities and limitations of the cytologic method are taken into consideration. A brief description of all nosological entities mentioned in the classification is given.

Osteoblastoma: classification and report of 16 patients.

In 16 patients who had osteoblastoma treated within the last eight years, the lesions can be classified as vertebral (four cases), central "benign" (seven cases), "aggressive" (three cases) and periosteal (two cases). The radiographic features were highly variable except for the consistent shell of reactive periosteal bone. None of the lesions resembled osteoid osteoma or osteosarcoma. The histological pattern was typical, showing sheets of osteoblasts forming irregular, poorly ossified bone trabeculae in a fibrovascular stroma. The three "aggressive" lesions had a distinctly more ominous histologic pattern, a more destructive radiographic appearance and recurred promptly following local curettage. Treatment varied, but for the vertebral, benign "central," and periosteal osteoblastomas, curettage or marginal resection was generally curative. Local wide resection was required for individual aggressively growing tumors.

The WHO classification of bone tumors.

The WHO scheme of classification of bone tumors is based on histologic criteria. It simply lists the main types of primary bone tumors; knowledge of histogenesis or of tumor origin is implied only for certain groups of lesions. This international agreement on nomenclature and classification of bone tumors would greatly aid comparative population studies on bone tumors in different parts of the world.

Osteoid osteoma and osteoblastoma: reclassification of 43 cases using Schajowicz's classification.

Forty-three cases of benign osteoblastic tumour of bone from the University of British Columbia bone tumour registry have been reviewed and reclassified according to the classification of Schajowicz and Lemos. Their classification has the advantage that the relationship of the two lesions is recognized and overlap, both radiologically and microscopically, is allowed for. The terminology used in the new classification, however, is cumbersome and confusing and appears to be of no great advantage. We therefore recommend instead the terminology modified from that of Dias and Frost, which incorporates the observations put forth by Schajowicz and Lemos: (a) cortical osteoblastoma, (b) medullary osteoblastoma, (c) periosteal osteoblastoma and (d) multifocal osteoblastoma.

[The international classification of bone tumors and some remarks concerning it]. / Mezhdunarodmaia klassifidatsiia opukholei kostei i nekotorye zamechaniia k nei

The international histological classification of bones has been issued by the World Health Organization in 1972. The article discusses merits of the classification, its importance in unification of the nomenclature on bone tumours, in studies of their nature and histogenesis, etc. At the same time some drawbacks of the classification are noted: lack of accuracy with respect to the nomenclature and grouping of the so-called giant-cell tumours of bones, with respect to the group of tumours of the "bone marrow", the group of mesenchymomas, etc. The author makes his critical notes on the basis of the experience gained by his co-workers and by himself.