A total of 296 tumour and tumour – like lesions of the bone were studied between 1990 and 2003 (14 years) in Goa medical college and we report the utility of FNAC in the diagnosis of osteosarcomas. Osteosarcomas comprised 31 cases out of 296 and they were the most common malignant primary bone tumor. Of these 27 were conventional osteosarcomas, 2 cases were small cell osteosarcomas, one case was telangiectatic type of osteosarcoma and one was multicentric or multifocal osteosarcoma. In this paper the utility of FNAC in these lesions along with the clinical and radiological correlation is also discussed. For the diagnosis of osteosarcoma great importance is to be given to the age of the patient, site in the bone, type of bone affected, the radiologic and the cytologic picture. The cytology smears are hypercellular or moderately cellular with hyperchromatic, pleomorphic, bizarre cells, mononuclear as well as multinucleated tumour giant cells with osteoid. The cytology must be evaluated in a total clinical – radiological and pathological scenario. Small cell osteosarcomas can be confused with Ewing's sarcoma and malignant lymphoma. Telangiectatic osteosarcomas yields mainly blood on aspiration. FNAC is also invaluable in the diagnosis of multicentric or multifocal osteosarcoma.

Key words : aspiration, osteosarcoma