[Osteocartilaginous exostoses (osteochondromas)].

Osteochondroma is the most common true bone neoplasm formed by a cartilage capped bony projection arising on the external surface of a bone containing a marrow cavity that is continuous with that of the underlying bone. Osteochondromas generally arise in the bones preformed by cartilage. Osteochondromas may be solitary and multiple. Most reported cases have been in the first 3 decades with no known sex predilection. The lesion has three layers - perichondrium, cartilage and bone. The cartilage cap is usually less than 2.0 cm thick, superficial chondrocytes are clustered, the ones close to the transition to the bone resemble a growth plate, they are organized into chords and undergo enchondrial ossification. Loss of the architecture of cartilage, wide fibrous bands, myxoid change, increased chondrocyte cellularity, mitotic activity, significant chondrocyte atypia and necrosis are all features that may indicate secondary malignant transformation.

[Osteochondrosarcoma: clinical and morphological comparisons].

A total of 109 patients with chondrosarcoma were operated on in 2005-2007. Classical primary chondrosarcoma was verified in 77 cases; secondary and periosteal chondrosarcomas were confirmed in 28 and 4 patients, respectively. By analyzing their findings and the data available in the literature, the authors considered the current problems in the classification and diagnosis of the most common types of cartilaginous malignancies. New techniques, including cytogenetic assay, significantly alleviate this problem. However, the most precise cytogenetic assays are expensive and not always accessible for usual oncological care. The principal criteria in practice are a clinical picture, the results of radiation studies, and the standard histological method that establishes the differentiation of chondrosarcoma, the extent of a process, and the specific features of tumor growth. Immunohistochemical assay are of no crucial importance. In some cases, fine-needle biopsy may provide useful information to make a decision on treatment policy.