Fine-needle aspiration diagnosis of giant cell tumour of bone presenting at unusual sites.

Giant cell tumour (GCT) of bone is a distinctive neoplasm, which has only recently been included within the diagnostic purview of the cytopathologist. Four cases of GCT of bone diagnosed primarily and exclusively by fine needle aspiration cytology (FNAC), presenting at unusual sites, are presented with a view to highlight the cytomorphologic features of this tumour and its differential diagnosis on FNAC. Each of these cases were distinctive by virtue of their localisation, but presented as classical expansile osteolytic lesions roentgenologically. Despite the paucity of literature regarding the cytodiagnosis of these lesions, the authors nevertheless recommend FNAC as a primary tool in the diagnosis of these lesions. Copyright 2002 Wiley-Liss, Inc.