Younus Soomro ( Department of Orthopaedics, Civil Hospital and Dow Medical College, Karachi. )
Asim Hussain ( Department of Orthopaedics, Civil Hospital and Dow Medical College, Karachi. )
The giant cell tumour (osteoclastoma) account for only 4% of all bony tumours1. Tumour of the patella are rare but whenever they occur the commonest is the giant cell tumour2. The classic location is around the knee joint and it starts in the epiphysis spreading to the metaphysis and may erode the contex in 25% of the cases. Approximately 10% of these tumours have a malignant course3.
Giant cell tumour is a tumour of mesenchymal origin. These tumours have osteoclasts which look like multi-nucleated giant cells4. There are ultra-structural similarities between giant cells and osteoclasts as both contain large number of mitochondria, poorly developed endoplasmic reticulum which gives it the name and is distributed in a background of plump spindle shaped fibroblast like cells5. Although giant cells are present in some other bony tumours like aneurysmal bone cyst, hyperparathyroidism, osteoblastoma but the cardinal feature of differentiation is the regular distribution and arrangement of these giant cells. It is the anaplasia in spindle celis on which the tumour is histologically classified from grade I to III7. After a period of time or after resection the tumour may recur and produce a picture of malignancy8. Total excision is the treatment of choice. If the lesion is in a bone then curettage with bone grafting gives good results although the chances of recurrence are about 25 to 40%. Radiotherapy has not yielded any better results but only increases the possibility of malignancy.
1. Dajlin, D.C. Giant cell tumour (osteoclastoma), in bone tumoura. 2nd ed. Springfield, Thomas, 1967,pp. 78-79.
2. Kransdorf M.J., Moaer, R.P., Vinh, T.N. and Callaghan, J.J. Primary tumoura of the patella: a review of 42 cases. Sk eletal Radiol., 1989;18:365-71.
3. Carneaale, P.G. Sometimes malignant tumoura of hone, in Camphell\\\'s operative orthopaedics. 7th ed. St. Louia, Moaby, 1987, pp. 765-805.
4. Yoahida,H.,AJteho, M. and Yumoto,T.Giantcell tumourhone. Enzymehiatochemical, biochemicaland tiasuecultureatudiea.VirchowsArch. (PathoLAnat.), 1982;395:319-30.
5. Robbina, S.L,Cotran, itS, and Kumar, V. The musculoskeletal ayatem, in pathological basis ofdiaeaae. 3rd ed. Philadelphia, Saundera, 1984, pp. 1345-46
6 American Registry of Pahology. Tumoura of uncertain origin, in tumourof hone and cartilage. Edited by H.J. Spjut, H.D. Dorfman, WE. Pechner and LV. Ackerman. Armed Forcealnatitute of Pathologyy, Washington, 1970, pp.312-13.
7. Sartcrkin, N.G. Malignancy, aggreasiveneaa and recurrence ingiant cell tumourof bone. Cancer, 1980;46:1641-49.
8. Dahlin, D.C., Cuppe, R.E and Johnson, E.W. Jr. Giantcell tumour: A study of 195 cases. Cancer, 1970;25:1061-70.