The histogenesis of giant cell tumour of bone: a model of interaction between neoplastic cells and osteoclasts

Giant cell tumour df bone (GCT) is a benign primary neoplasm of a bone char acterised by distinctive clinical, radiological and pathological features. Females are slightly more often affected than males, and the majority of pa tients present between the ages of 20 and 50. GCT is locally aggressive and produces expansive and lytic lesions, most commonly in the epiphyses of lo ng tubular bones. Histologically, it is composed of oval and spindle mononu clear cells, uniformly distributed amongst which are large multinucleated o steoclast-like giant cells. Although the term "Giant Cell Tumour" (and the erroneous historical term 'osteoclastoma') may imply that it is the multinu cleated giant cells which are responsible for the proliferative capacity of the tumour, there is evidence that the stromal-like cells, the major compo nent of the mononuclear cell population, represent the true neoplastic comp onent of the neoplasm. The diagnosis and management of conventional GCT are often challenging and there is considerable current interest in its pathob iology. The precise histogenesis of GCT and the nature of its varying cellu lar constituents have remained a matter of some controversy. Factors influe ncing the clinical course and biological aggression of GCT are also unclear . In this selective review, the clinicopathological characteristics of GCT are summarised and current areas of interest in the study of the neoplasm a re presented and discussed. Lastly, a hypothetical model of the mechanism o f histogenesis and the biological behaviour of GCT is presented.